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From: Dave Reisner <d@falconindy.com>
To: linux-kernel@vger.kernel.org
Cc: tj@kernel.org
Subject: Initramfs FSID altered in 3.14
Date: Thu, 3 Apr 2014 13:57:44 -0400	[thread overview]
Message-ID: <20140403175744.GE585@rampage> (raw)

Hi,

[This is a repost of a G+ post at Tejun's request]

With Linux 3.14, you might notice in /proc/self/mountinfo that your
root's parent FSID is now 0, instead of the 1 that it's been for the
last N years. Tejun wrote the change (9e30cc9595303b27b48) that caused
this, but the change comes in a rather innocuous way. Instead of an
internal kernel mount of sysfs being assigned 0, it's now the initramfs.

So far, this has already caused switch_root and findmnt (from
util-linux) to break, cp (from coreutils) to break when using the -x
flag in early userspace, and it's also been pointed out that systemd's
readahead code makes assumptions about a device number of 0.

Are we now supposed to go and change all the assumptions in userspace
about 0 being special? I'm conflicted. The kernel isn't supposed to
break userspace, but it seems to me that FSIDs were never something to
rely on -- similar to the block device numbering scheme.

Cheers,
Dave

             reply	other threads:[~2014-04-03 17:57 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-03 17:57 Dave Reisner [this message]
2014-04-03 18:13 ` Initramfs FSID altered in 3.14 Thomas Bächler
2014-04-03 19:16   ` Tejun Heo
2014-04-03 19:20     ` Theodore Ts'o
2014-04-03 22:02       ` Alexandre Demers
2014-04-03 19:49     ` [PATCH] fs: Don't return 0 from get_anon_bdev Thomas Bächler
2014-04-03 19:51       ` Tejun Heo
2014-04-03 19:51         ` Tejun Heo
2014-04-03 19:55         ` [PATCHv2] " Thomas Bächler
2014-04-03 20:32           ` Greg KH
2014-04-03 20:32             ` Greg KH
2014-04-03 20:21       ` [PATCH] " H. Peter Anvin
2014-04-03 23:41       ` Alexandre Demers
2014-04-03 18:57 ` Initramfs FSID altered in 3.14 Pádraig Brady
2014-04-03 19:13 ` Tejun Heo

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