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author | Anton Eidelman <anton@lightbitslabs.com> | 2019-08-12 23:00:36 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-10 10:35:21 +0100 |
commit | e1031b6c8100dba0da0d672f98db3a03139a3f93 (patch) | |
tree | a3381a6a7247cef23fe5758495caeadd1bacd144 | |
parent | 6950d5b64a15407f10959f8a2e634ee65c576aea (diff) | |
download | linux-stable-e1031b6c8100dba0da0d672f98db3a03139a3f93.tar.gz linux-stable-e1031b6c8100dba0da0d672f98db3a03139a3f93.tar.bz2 linux-stable-e1031b6c8100dba0da0d672f98db3a03139a3f93.zip |
nvme-multipath: fix possible I/O hang when paths are updated
[ Upstream commit 504db087aaccdb32af61539916409f7dca31ceb5 ]
nvme_state_set_live() making a path available triggers requeue_work
in order to resubmit requests that ended up on requeue_list when no
paths were available.
This requeue_work may race with concurrent nvme_ns_head_make_request()
that do not observe the live path yet.
Such concurrent requests may by made by either:
- New IO submission.
- Requeue_work triggered by nvme_failover_req() or another ana_work.
A race may cause requeue_work capture the state of requeue_list before
more requests get onto the list. These requests will stay on the list
forever unless requeue_work is triggered again.
In order to prevent such race, nvme_state_set_live() should
synchronize_srcu(&head->srcu) before triggering the requeue_work and
prevent nvme_ns_head_make_request referencing an old snapshot of the
path list.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r-- | drivers/nvme/host/multipath.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 747c0d4f9ff5..304aa8a65f2f 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -420,6 +420,7 @@ static void nvme_mpath_set_live(struct nvme_ns *ns) srcu_read_unlock(&head->srcu, srcu_idx); } + synchronize_srcu(&ns->head->srcu); kblockd_schedule_work(&ns->head->requeue_work); } |