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Date:   Tue, 22 Nov 2022 10:58:48 -0600
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Subject: Re: [PATCH] scsi:iscsi: Record session's startup mode in kernel
Content-Language: en-US
To:     Wenchao Hao <haowenchao@huawei.com>, Lee Duncan <lduncan@suse.com>,
        Chris Leech <cleech@redhat.com>,
        "James E . J . Bottomley" <jejb@linux.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        open-iscsi@googlegroups.com, linux-scsi@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, liuzhiqiang26@huawei.com,
        linfeilong@huawei.com
References: <20221122213040.4128105-1-haowenchao@huawei.com>
From:   Mike Christie <michael.christie@oracle.com>
In-Reply-To: <20221122213040.4128105-1-haowenchao@huawei.com>
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On 11/22/22 3:30 PM, Wenchao Hao wrote:
> There are 3 iscsi session's startup mode which are onboot, manual and
> automatic. We can boot from iSCSI disks with help of dracut's service
> in initrd, which would set node's startup mode to onboot, then create
> iSCSI sessions.
> 
> While the configure of onboot mode is recorded in file of initrd stage
> and would be lost when switch to rootfs. Even if we update the startup
> mode to onboot by hand after switch to rootfs, it is possible that the
> configure would be covered by another discovery command.
> 
> root would be mounted on iSCSI disks when boot from iSCSI disks, if the
> sessions is logged out, the related disks would be removed, which would
> cause the whole system halt.

The userspace tools check for this already don't they? Running iscsiadm
on the root disk returns a failure and message about it being in use.

Userspace can check the session's disks and see if they are mounted and
what they are being used for.