Re: REVIEW: Write primary superblock info to ALL secondaries during mkfs

Mark Goodwin
2008-03-26T01:54:16Z

Eric Sandeen wrote:
> Barry Naujok wrote:
>> Secondaries should contain redundant information from the primary
>> superblock. It does this for the filesystem geometry information,
>> but not inode values (rootino, rt inos, quota inos).
>>
>> This patch updates all the secondaries from the primary just before
>> it marks the filesystem as good to go.
>>
>> Unfortunately, this also affects the output of xfs_repair during
>> QA 030 and 178 which restores the primary superblock from the
>> secondaries.
>>
>> Now that the secondaries have valid inode values, xfs_repair
>> does not have to restore them to the correct values after copying
>> the secondary into the primary.
>>
>> Attached is the mkfs.xfs patch and also the updated golden
>> outputs for QA 030 and 178.
>>
>> The next step after this is to enhance xfs_repair to be more
>> thorough in checking the secondaries during Phase 1.
>
> One related thing I'd always wondered about was stamping a secondary at
> the very end of the device (and therefore shrinking the fs by just a
> bit) - repair could then do a quick check at the end of the device
> before resorting to scanning for the 2nd backup... would this make any
> sense?

I guess it might, Barry what do you think? Probably makes grow a bit
more complicated. What would repair do if it doesn't find the backup
SB at the end of the device? We'd need a new SB flag to indicate it's
supposed to be there, which seems a bit chicken-and-egg'ish ...

Cheers

>
> -Eric
>
>

--

Mark Goodwin markgw@sgi.com
Engineering Manager for XFS and PCP Phone: +61-3-99631937
SGI Australian Software Group Cell: +61-4-18969583
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