Date: Mon, 27 Mar 2000 07:35:36 -0500 (EST) From: Kenneth W Cochran <kwc@world.std.com> To: freebsd-fs@freebsd.org Subject: Re: ext2fs optional features Message-ID: <200003271235.HAA09498@world.std.com>
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>From krentel@dreamscape.com Fri Mar 24 22:14:21 2000 >Date: Fri, 24 Mar 2000 22:10:50 -0500 (EST) >To: freebsd-fs@FreeBSD.ORG >Subject: ext2fs optional features >Cc: kwc@world.std.com > >This question was asked in -stable a couple days ago, but it >really belongs in -fs. Ok... >Recently, some changes were made to the ext2fs support that >prohibit R/W mounts for some newer ext2fs partitions with >optional features. I've seen this with Red Hat 6.1 and >Slackware 7. Red Hat 6.0 seems to use an older format. Check. Slackware 7 in my case. Ext2 filesystems made with Slackware 4 appear to do ok with FreeBSD's ext2 support. >This is what Linux's tune2fs reports: Hmmm, which distribution/kernel version? > # tune2fs -l /dev/sdb2 > tune2fs 1.15, 18-Jul-1999 for EXT2 FS 0.5b, 95/08/09 > Filesystem volume name: <none> > Last mounted on: <not available> > Filesystem UUID: 38a27662-0012-11d4-8f7a-ead76bc87798 > Filesystem magic number: 0xEF53 > Filesystem revision #: 1 (dynamic) > Filesystem features: sparse_super > Filesystem state: not clean > Errors behavior: Continue > Filesystem OS type: Linux > ... > >And this is what appears in the logs: > > Mar 24 21:36:47 blue /kernel: WARNING: R/W mount of dev 0x3040a > denied due to unsupported optional features Yep. That's what I get too. FreeBSD 3.4-stable (about a week "old" now) trying to access Linux (Slackware 7.0) ext2 filesystems. >What are the optional features? What does "sparse_super" do? >Does Linux actually use these features, or are they for future use? > >Is it possible to support R/W mounts with these features? > >I remember 3.4-release let me mount the same filesystem R/W. >Was I unknowingly corrupting the filesystem, or running some >risk of a panic? > >I noticed that tune2fs also reported: > > Block size: 4096 > Fragment size: 4096 > >Does Linux really not support fragments?? I was stunned. > >Much thanks for any answers. > >--Mark Krentel To Mark's questions I might add: (Most likely a Linux question...) Is there a way, perhaps in Linux with its tunefs, to adjust or "turn off" those "optional features" (other things too?) in such a way that FreeBSD's ext2 support will work? In other words, what would be an "optimal filesystem config" in Linux for FreeBSD's use? -kc To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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