From: Sweet Tea Dorminy <sweettea@redhat.com>
To: Dave Chinner <david@fromorbit.com>
Cc: Tony Asleson <tasleson@redhat.com>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
linux-scsi@vger.kernel.org, linux-block@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [RFC 9/9] __xfs_printk: Add durable name to output
Date: Mon, 6 Jan 2020 19:19:07 -0500 [thread overview]
Message-ID: <CAMeeMh-zr309TzbC3ayKUKRniat+rzurgzmeM5LJYMFVDj7bLA@mail.gmail.com> (raw)
In-Reply-To: <20200106220233.GK23195@dread.disaster.area>
> > >> +
> > >> if (mp && mp->m_fsname) {
> > >
> > > mp->m_fsname is the name of the device we use everywhere for log
> > > messages, it's set up at mount time so we don't have to do runtime
> > > evaulation of the device name every time we need to emit the device
> > > name in a log message.
> > >
> > > So, if you have some sooper speshial new device naming scheme, it
> > > needs to be stored into the struct xfs_mount to replace mp->m_fsname.
> >
> > I don't think we want to replace mp->m_fsname with the vpd 0x83 device
> > identifier. This proposed change is adding a key/value structured data
> > to the log message for non-ambiguous device identification over time,
> > not to place the ID in the human readable portion of the message. The
> > existing name is useful too, especially when it involves a partition.
>
> Oh, if that's all you want to do, then why is this identifier needed
> in every log message? It does not change over the life of the
> filesystem, so it the persistent identifier only needs to be emitted
> to the log once at filesystem mount time. i.e. instead of:
>
> [ 2.716841] XFS (dm-0): Mounting V5 Filesystem
>
> It just needs to be:
>
> [ 2.716841] XFS (dm-0): Mounting V5 Filesystem on device <persistent dev id>
>
> If you need to do any sort of special "is this the right device"
> checking, it needs to be done immediately at mount time so action
> can be taken to shutdown the filesystem and unmount the device
> immediately before further damage is done....
>
> i.e. once the filesystem is mounted, you've already got a unique and
> persistent identifier in the log for the life of the filesystem (the
> m_fsname string), so I'm struggling to understand exactly what
> problem you are trying to solve by adding redundant information
> to every log message.....
>
Log rotation loses that identifier though; there are plenty of setups
where a mount-time message has been rotated out of all logs by the
time something goes wrong after a month or two.
next prev parent reply other threads:[~2020-01-07 0:19 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-23 22:55 [RFC 0/9] Add persistent durable identifier to storage log messages Tony Asleson
2019-12-23 22:55 ` [RFC 1/9] lib/string: Add function to trim duplicate WS Tony Asleson
2019-12-23 23:28 ` Matthew Wilcox
2020-01-02 22:52 ` Tony Asleson
2020-01-03 14:30 ` Tony Asleson
2019-12-23 22:55 ` [RFC 2/9] printk: Bring back printk_emit Tony Asleson
2019-12-23 22:55 ` [RFC 3/9] printk: Add printk_emit_ratelimited macro Tony Asleson
2019-12-23 22:55 ` [RFC 4/9] struct device_type: Add function callback durable_name Tony Asleson
2019-12-23 22:55 ` [RFC 5/9] block: Add support functions for persistent durable name Tony Asleson
2019-12-23 22:55 ` [RFC 6/9] create_syslog_header: Add " Tony Asleson
2019-12-24 0:54 ` James Bottomley
2020-01-02 22:53 ` Tony Asleson
2019-12-23 22:55 ` [RFC 7/9] print_req_error: Add persistent " Tony Asleson
2019-12-23 22:55 ` [RFC 8/9] ata_dev_printk: Add durable name to output Tony Asleson
2019-12-24 0:56 ` James Bottomley
2019-12-23 22:55 ` [RFC 9/9] __xfs_printk: " Tony Asleson
2020-01-04 2:56 ` Dave Chinner
2020-01-06 2:45 ` Tony Asleson
2020-01-06 22:02 ` Dave Chinner
2020-01-07 0:19 ` Sweet Tea Dorminy [this message]
2020-01-07 1:23 ` Dave Chinner
2020-01-07 17:01 ` Tony Asleson
2020-01-08 2:10 ` Dave Chinner
2020-01-08 16:53 ` Tony Asleson
2020-01-09 1:41 ` Alasdair G Kergon
2020-01-09 23:22 ` Dave Chinner
2020-01-10 1:28 ` Alasdair G Kergon
2020-01-10 16:13 ` Tony Asleson
2019-12-24 0:50 ` [RFC 0/9] Add persistent durable identifier to storage log messages James Bottomley
2020-01-02 22:52 ` Tony Asleson
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