Bug 709867

Summary:	'btrfs device scan' not showing btrfs filesystems
Product:	[Fedora] Fedora	Reporter:	Michael Wiktowy <michael.wiktowy>
Component:	btrfs-progs	Assignee:	Josef Bacik <josef>
Status:	CLOSED NOTABUG	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	15	CC:	jbacik, josef, mmahut
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-06-01 20:43:24 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:

Description Michael Wiktowy 2011-06-01 19:57:17 UTC

Description of problem:
After installing F15 on root with a btrfs filesystem, running 'btrfs device scan' only displays "Scanning for Btrfs filesystems" and then returns to the command prompt.

Version-Release number of selected component (if applicable):
btrfs-progs-0:0.19-13.fc15.i686

How reproducible:
Always

Steps to Reproduce:
1. Have root (/) partition as btrfs
2. Run 'btrfs device scan' as root
  
Actual results:
Empty list when 'mount' clearly shows a btrfs filesystem

Expected results:
Showing device with some details about btrfs filesystem

Additional info:
I am new to btrfs and maybe am misinterpreting what the btrfs utility should do/display. But as a naive administrator, I would expect 'btrfs device scan' to show all btrfs partitions attached to the system, whether they are mounted or not and possibly details on any subvolumes.

Comment 1 Josef Bacik 2011-06-01 20:43:24 UTC

btrfs device scan searches all devices and adds them to the btrfs device cache.  This is so that btrfs knows how to put together multi-disk devices, so really should only be executed on boot, so users should never have to use the command.

Comment 2 Michael Wiktowy 2011-06-01 22:07:27 UTC

OK ... Thank you for your response.

It looks like 'btrfs filesystem show' gives me the info I was trying to get.

I would suggest an addition to the --help and man info mentioning the addition to the btrfs device cache functionality and that it should only be executed on boot.

Right now the text is too brief to be instructive.