From: NeilBrown <neilb@suse.com>
To: linux-raid@vger.kernel.org
Cc: shli@fb.com, kernel-team@fb.com, dan.j.williams@intel.com,
hch@infradead.org, liuzhengyuang521@gmail.com,
liuzhengyuan@kylinos.cn, Song Liu <songliubraving@fb.com>
Subject: Re: [PATCH v5 6/8] md/r5cache: sysfs entry r5c_state
Date: Wed, 19 Oct 2016 13:19:30 +1100 [thread overview]
Message-ID: <87lgxlxeq5.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <20161013054944.1038806-7-songliubraving@fb.com>
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On Thu, Oct 13 2016, Song Liu wrote:
> r5c_state have 4 states:
> * no-cache;
> * write-through (write journal only);
> * write-back (w/ write cache);
> * cache-broken (journal missing or Faulty)
I don't like this.
We already have a mechanism for removing a failed device from
an array: write 'remove' to the 'state' file in the relevant dev-*
subdirectory.
You can also use that file to tell if the journal has failed.
Please call the file something a little more obvious that 'r5c_state',
maybe 'journal_mode', and use it only to switch between write-through
and write-back.
If there is no journal, then either remove the file, or have writes fail
and reads return something obvious ... maybe ENODEV.
Thanks,
NeilBrown
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next prev parent reply other threads:[~2016-10-19 2:19 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-13 5:49 [PATCH v5 0/8] raid5-cache: enabling cache features Song Liu
2016-10-13 5:49 ` [PATCH v5 1/8] md/r5cache: Check array size in r5l_init_log Song Liu
2016-10-13 5:49 ` [PATCH v5 2/8] md/r5cache: move some code to raid5.h Song Liu
2016-10-13 5:49 ` [PATCH v5 3/8] md/r5cache: State machine for raid5-cache write back mode Song Liu
2016-10-14 6:13 ` NeilBrown
2016-10-14 7:03 ` Song Liu
2016-10-13 5:49 ` [PATCH v5 4/8] md/r5cache: write part of r5cache Song Liu
2016-10-14 6:53 ` NeilBrown
2016-10-14 7:33 ` Song Liu
2016-10-19 0:53 ` NeilBrown
2016-10-21 20:42 ` Song Liu
2016-10-13 5:49 ` [PATCH v5 5/8] md/r5cache: reclaim support Song Liu
2016-10-19 2:03 ` NeilBrown
2016-10-21 21:04 ` Song Liu
2016-10-13 5:49 ` [PATCH v5 6/8] md/r5cache: sysfs entry r5c_state Song Liu
2016-10-19 2:19 ` NeilBrown [this message]
2016-10-21 21:20 ` Song Liu
2016-10-13 5:49 ` [PATCH v5 7/8] md/r5cache: r5c recovery Song Liu
2016-10-19 2:32 ` NeilBrown
2016-10-20 3:03 ` NeilBrown
2016-10-21 21:12 ` Song Liu
2016-10-26 1:18 ` NeilBrown
2016-10-13 5:49 ` [PATCH v5 8/8] md/r5cache: handle SYNC and FUA Song Liu
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