Bug 1002032

Summary:	mke2fs can't return the correct filesystem type when blockscount is less than 2048 for ext3
Product:	Red Hat Enterprise Linux 7	Reporter:	bfan
Component:	libguestfs	Assignee:	Richard W.M. Jones <rjones>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	7.0	CC:	leiwang, wshi
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	libguestfs-1.22.6-5.el7	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2014-06-13 12:57:16 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description bfan 2013-08-28 11:12:45 UTC

Description of problem:
For creating ext3 filesystem, When "blockscount" option is less than 2048, mke2fs will create a ext2 filesystem
It looks like an ext3 filesystem issue, we can't know the details reason of ext3/mke2fs, So if we can do nothing in libguestfs, it would be better to add a note to the documentation


Version-Release number of selected component (if applicable):
libguestfs-1.22.6-4.el7.x86_64


How reproducible:
Always


Steps to Reproduce:
# guestfish -N fs mke2fs /dev/sda1 fstype:ext3 blockscount:2048 : list-filesystems
/dev/sda1: ext3
# guestfish -N fs mke2fs /dev/sda1 fstype:ext3 blockscount:2049 : list-filesystems
/dev/sda1: ext3
# guestfish -N fs mke2fs /dev/sda1 fstype:ext3 blockscount:2047 : list-filesystems
/dev/sda1: ext2


Actual results:
Output is ext2 when fstype:ext3 blockscount:2047


Expected results:
Output should be ext3 when fstype:ext3 blockscount:2047


Additional info:
Has same issue in rhel6, libguestfs-1.20.10-3.el6.x86_64

Comment 1 Richard W.M. Jones 2013-08-28 11:42:22 UTC

As discussed on IRC, the problem is that the filesystem
isn't large enough to contain a journal.  mke2fs prints
the warning message:

  Filesystem too small for a journal

This message is normally eaten by libguestfs, although
you can see it if you enable debugging.  The warning
doesn't stop mke2fs; it goes ahead and creates a filesystem
without a journal, a.k.a. ext2.

Anyway, we should document that this may happen.

BTW don't confuse "blockscount" (size of the filesystem
in blocks) with block size.

Comment 2 Richard W.M. Jones 2013-08-29 13:00:32 UTC

https://github.com/libguestfs/libguestfs/commit/1c8986e45c3f1a7e2391bde2848667332495e3aa

Comment 3 Richard W.M. Jones 2013-08-29 14:22:47 UTC

Fix also included in libguestfs-1.20.10-4.el6 (note
there is no separate bug for RHEL 6, I just included
the fix in the routine build).

Comment 5 bfan 2013-12-03 09:26:11 UTC

Verified with libguestfs-1.22.6-16.el7.x86_64

><fs> help mke2fs

DESCRIPTION
    "mke2fs" is used to create an ext2, ext3, or ext4 filesystem on
    "device".

    The optional "blockscount" is the size of the filesystem in blocks. If
    omitted it defaults to the size of "device". Note if the filesystem is
    too small to contain a journal, "mke2fs" will silently create an ext2
    filesystem instead.


Help out is update

Comment 6 Ludek Smid 2014-06-13 12:57:16 UTC

This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.