[lvm-devel] 答复： Re: [PATCH 1/1] added resizing for btrfs

[Zhen Ren]

Hi,

Sorry for the delay.

>>> Marcus Müller <mueller at kit.edu> 2017-8-24 pm 15:25 >>>
Hi Eric,

>>ha! Nearly escaped my memory.

>>Re: your (justified) objections:

> 1. lack "check" action in your script
> In patch [1], it uses "btrfs scrub", which I think you can replace it
> with "btrfs check".

>>1. You're right; `btrfs scrub` just checks the file/metadata checksums 
>>on a live system (and can thus correct /file breakage/), whereas `btrfs 
>>check` checks for structural damage.

>>I'm not sure `btrfs scrub` is the right thing to do – certainly, it will 
>>detect corrupted blocks; but as far as I can see, these aren't a problem 
>>at all during resizing; they would be moved untouched.

>>I'm, on the other hand, also not sure we should implement anything here 
>>– other filesystem checks are simply skipped if the filesystem is 
>>already mounted (and mounting is a requirement for resizing). `btrfs 
>>check` would take a long time.

Yeah, I overlooked this potential problem. IMHO, fsadm should have a option to
decide if "check" is required after resize.

>>So, either btrfs check or a nop; either is fine with me, what would you 
>>prefer?

Hmm, the SUSE-specific patch was reviewed by btrfs-tools maintainer David Sterba, and tested
by btrfs guys. I'd suggest to keep the way to check with "btrfs scrub" as in that patch.

Please send v2 after your changes, and I'll get the v2 patch, test it and then send the respective
test script for Zdenek review.

Thanks!
Eric