Bug 1855292

Summary: btrfs is not resizable in anaconda
Product: [Fedora] Fedora Reporter: Kamil Páral <kparal>
Component: anacondaAssignee: Anaconda Maintenance Team <anaconda-maint-list>
Status: CLOSED DUPLICATE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: rawhideCC: anaconda-maint-list, bugzilla, davide, gmarr, jkonecny, jonathan, kellin, robatino, vanmeeuwen+fedora, vponcova, vtrefny, wwoods
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Whiteboard: RejectedBlocker
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Last Closed: 2020-07-23 08:46:34 UTC Type: Bug
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partitioning screen screenshot none

Description Kamil Páral 2020-07-09 13:36:30 UTC 
Created attachment 1700452 [details]
partitioning screen screenshot

Description of problem:
When I select a btrfs partition in guided partitioning, the partition is marked as "not resizeable". So it's not possible to shrink it in order to install Fedora on the same disk. I found out when doing https://fedoraproject.org/wiki/QA:Testcase_partitioning_guided_shrink as part of https://fedoraproject.org/wiki/Test_Day:2020-07-08_Btrfs_default .

I'm not sure whether this is a bug or an intentionally missing functionality. I'm also not sure whether it's a blocker according to https://fedoraproject.org/wiki/Fedora_33_Final_Release_Criteria#storage-volume-resize (or some other one) or not. Proposing for discussion.

Version-Release number of selected component (if applicable):
anaconda-33.20-1.1.btrfs.fc33.x86_64

How reproducible:
always

Steps to Reproduce:
1. install Fedora with btrfs
2. boot installer again, and try to shrink the existing btrfs partition in guided partitioning. It's marked as not resizeable.
Comment 1 Vojtech Trefny 2020-07-09 13:55:52 UTC 
> I'm not sure whether this is a bug or an intentionally missing functionality.

Blivet doesn't support resizing of btrfs so it is a missing functionality. Support for filesystem resizing was always very limited, we actually only support resizing of Ext and NTFS.
Comment 2 Chris Murphy 2020-07-09 14:14:29 UTC 
The resize of Btrfs is theoretically safer because it can only done online and all the code is in the kernel. But it's logistically challenging because the user could have presented the installer with a multiple-device Btrfs file system. And in that case, it's immediately suboptimal (or possibly difficult) to do a resize without a more sophisticated UI to indicate which device is to be shrunk; or even shrinking multiple devices by different amounts. A possible solution is to consider a Btrfs file system resizeable only if it is is a single device volume.

I agree it's not a blocker.
Comment 3 Chris Murphy 2020-07-09 14:19:08 UTC 
And by "sophisticated" I also mean "complicated".
Comment 4 Geoffrey Marr 2020-07-20 19:02:24 UTC 
Discussed during the 2020-07-20 blocker review meeting: [0]

The decision to classify this bug as a "RejectedBlocker" was made as while it would be nice to have this feature, we agree the criteria are not intended to require it, and we have substantial precedent for not being able to shrink our own default filesystem layouts.

[0] https://meetbot.fedoraproject.org/fedora-blocker-review/2020-07-20/f33-blocker-review.2020-07-20-16.18.txt
Comment 5 Vojtech Trefny 2020-07-23 08:46:34 UTC 

*** This bug has been marked as a duplicate of bug 962143 ***