From: NeilBrown <neilb@suse.com>
To: Artur Paszkiewicz <artur.paszkiewicz@intel.com>, shli@kernel.org
Cc: linux-raid@vger.kernel.org
Subject: Re: [PATCH v2 09/12] raid5-ppl: read PPL signature from IMSM metadata
Date: Thu, 08 Dec 2016 10:27:58 +1100 [thread overview]
Message-ID: <87inqv2ubl.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <0e661d59-033e-6797-b5d1-d30cdb04ef11@intel.com>
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On Thu, Dec 08 2016, Artur Paszkiewicz wrote:
> On 12/07/2016 02:25 AM, NeilBrown wrote:
>> On Tue, Dec 06 2016, Artur Paszkiewicz wrote:
>>
>>> The PPL signature is used to determine if the stored PPL is valid for a
>>> given array. With IMSM, the PPL signature should match the
>>> orig_family_num field of the superblock. To avoid passing this value
>>> from userspace, it can be read from the IMSM MPB when initializing the
>>> log.
>>
>> It is up to mdadm to determine if the PPL is valid. It would only tell
>> the kernel that a PPL exists if it is valid...
>
> The kernel also has to know this value because it writes it to the PPL
> header. So yet another sysfs attribute just for this value? How about
> adding a directory similar to "bitmap" to hold all the PPL related
> settings?
There is only one PPL header (per device) - correct?
md can read that header, change the few fields that it knows about, and
write it back out again. Does it ever need to change the PPL signature?
When a PPL is created, mdadm can write the initial header.
Am I missing something?
Thanks,
NeilBrown
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next prev parent reply other threads:[~2016-12-07 23:27 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-05 15:31 [PATCH v2 00/12] Partial Parity Log for MD RAID 5 Artur Paszkiewicz
2016-12-05 15:31 ` [PATCH v2 01/12] raid5-cache: move declarations to separate header Artur Paszkiewicz
2016-12-05 15:31 ` [PATCH v2 02/12] raid5-cache: add policy logic Artur Paszkiewicz
2016-12-05 15:31 ` [PATCH v2 03/12] raid5-cache: add a new policy Artur Paszkiewicz
2016-12-07 0:46 ` NeilBrown
2016-12-07 14:36 ` Artur Paszkiewicz
2016-12-07 23:24 ` NeilBrown
2016-12-08 10:28 ` Artur Paszkiewicz
2016-12-08 21:22 ` NeilBrown
2016-12-05 15:31 ` [PATCH v2 04/12] md: superblock changes for PPL Artur Paszkiewicz
2016-12-05 15:31 ` [PATCH v2 05/12] raid5-ppl: Partial Parity Log implementation Artur Paszkiewicz
2016-12-06 1:06 ` kbuild test robot
2016-12-07 1:17 ` NeilBrown
2016-12-07 14:37 ` Artur Paszkiewicz
2016-12-05 15:31 ` [PATCH v2 06/12] raid5-ppl: calculate partial parity Artur Paszkiewicz
2016-12-05 15:31 ` [PATCH v2 07/12] md: mddev_find_container helper function Artur Paszkiewicz
2016-12-07 1:23 ` NeilBrown
2016-12-05 15:31 ` [PATCH v2 08/12] md: expose rdev->sb_start as sysfs attribute Artur Paszkiewicz
2016-12-07 1:25 ` NeilBrown
2016-12-05 15:31 ` [PATCH v2 09/12] raid5-ppl: read PPL signature from IMSM metadata Artur Paszkiewicz
2016-12-07 1:25 ` NeilBrown
2016-12-07 14:38 ` Artur Paszkiewicz
2016-12-07 23:27 ` NeilBrown [this message]
2016-12-08 10:36 ` Artur Paszkiewicz
2016-12-05 15:31 ` [PATCH v2 10/12] raid5-ppl: recovery from dirty shutdown using PPL Artur Paszkiewicz
2016-12-05 15:31 ` [PATCH v2 11/12] raid5-ppl: support disk add/remove with distributed PPL Artur Paszkiewicz
2016-12-07 1:29 ` NeilBrown
2016-12-05 15:31 ` [PATCH v2 12/12] raid5-ppl: runtime PPL enabling or disabling Artur Paszkiewicz
2016-12-07 0:32 ` [PATCH v2 00/12] Partial Parity Log for MD RAID 5 NeilBrown
2016-12-07 14:36 ` Artur Paszkiewicz
2016-12-07 17:09 ` Shaohua Li
2016-12-13 15:25 ` Jes Sorensen
2016-12-14 19:47 ` Shaohua Li
2016-12-15 11:44 ` Artur Paszkiewicz
2016-12-16 23:24 ` Shaohua Li
2017-01-03 15:42 ` Jes Sorensen
2017-01-04 8:01 ` Artur Paszkiewicz
2017-01-04 13:29 ` Jes Sorensen
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