Sagi Grimberg 32aa0b3f0c nvme-multipath: fix possible hang in live ns resize with ANA access
commit 72e3b8883a36e80ebfa41015c7b6926ce31ace05 upstream.

When we revalidate paths as part of ns size change (as of commit
e7d65803e2bb), it is possible that during the path revalidation, the
only paths that is IO capable (i.e. optimized/non-optimized) are the
ones that ns resize was not yet informed to the host, which will cause
inflight requests to be requeued (as we have available paths but none
are IO capable). These requests on the requeue list are waiting for
someone to resubmit them at some point.

The IO capable paths will eventually notify the ns resize change to the
host, but there is nothing that will kick the requeue list to resubmit
the queued requests.

Fix this by always kicking the requeue list, and if no IO capable path
exists, these requests will be queued again.

A typical log that indicates that IOs are requeued:
--
nvme nvme1: creating 4 I/O queues.
nvme nvme1: new ctrl: "testnqn1"
nvme nvme2: creating 4 I/O queues.
nvme nvme2: mapped 4/0/0 default/read/poll queues.
nvme nvme2: new ctrl: NQN "testnqn1", addr 127.0.0.1:8009
nvme nvme1: rescanning namespaces.
nvme1n1: detected capacity change from 2097152 to 4194304
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
nvme nvme2: rescanning namespaces.
--

Reported-by: Yogev Cohen <yogev@lightbitslabs.com>
Fixes: e7d65803e2bb ("nvme-multipath: revalidate paths during rescan")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Cc: <stable@vger.kernel.org> # v5.15+
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-10-26 12:34:23 +02:00
2021-10-18 20:22:03 -10:00
2022-10-15 07:59:05 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Description
No description provided
Readme 5.7 GiB
Languages
C 97.6%
Assembly 1%
Shell 0.5%
Python 0.3%
Makefile 0.3%