Skip to contentSkip to conversation

Remount failure without fstab or mtab

DISCUSSION Phillip Susi 3 participants 3 messages Dec 17, 2014 – Dec 18, 2014 Util-Linux package

lore
Share & tools
lore

Phillip Susi

author
#0 lore raw

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

I have a bug report in debian about "mount -o remount,rw /" failing because /etc/fstab does not contain an entry for the root fs, and /proc is not mounted ( booting with init=/bin/bash for recovery ). I'm not sure whether this is really a bug or not so I thought I'd ask.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.17 (MingW32)

iQEcBAEBAgAGBQJUkaBIAAoJENRVrw2cjl5RrtcIAJZs/d8l/ijxBusuebPU1+NF EkCvlZMjbWLcQjI8nwidLQN9lZGEdj0Hhlm7kQjashiF5ti/YcJPFyCkEEruW+S+ WtC1l0DRlwCz7bjeO9WWPtInLen1hzAc2o3vmXq13AxoLcmi8/nwoodIT1z+FQOR JXugedrmarA17vakPddPzj3FOeJjgaZESiB4zj4uxXcxUWu6tfMaFSV00LlE58HI K9W1aBmYqcw5jVvpHaT5n5IUL4xGCmN3v7galnjErG5iTV1pd3N1B2hkakcv+Sjj Gza5U/Qpdj2zJ143m6WyVU0q1hL7qucuGMwnhtq8buYIjD+I/V/0/n7Zw+Norq0= =Qd1S
-----END PGP SIGNATURE-----

#1 lore raw
Quoted 4 lines · Phillip Susi

I have a bug report in debian about "mount -o remount,rw /" failing because /etc/fstab does not contain an entry for the root fs, and /proc is not mounted ( booting with init=/bin/bash for recovery ). I'm not sure whether this is really a bug or not so I thought I'd ask.

I'm not an expert on the Debian version of mount, but my understanding is that if there isn't a line in fstab/mtab, then the mount command must contain both the mount point and the block device because the underlying kernel call must be given both. Check the documentation of "remount" in your "mount" manual page.

Dale

maintainer
#2 lore raw
In reply to Phillip Susi
Quoted 4 lines · Phillip Susi

I have a bug report in debian about "mount -o remount,rw /" failing because /etc/fstab does not contain an entry for the root fs, and /proc is not mounted ( booting with init=/bin/bash for recovery ). I'm not sure whether this is really a bug or not so I thought I'd ask.

This is bug, kernel does not require <source> for MS_REMOUNT, so the current mount(8) behavior is too restrictive.

For standard use-case we want to read mtab (/proc/self/mountinfo) to gather all mount options for the mount syscall, but this behavior should be optional.

Fixed by commit 01966ce852ac6c46e7e35a8e4f981dea88620ff8,

Karel

Signature · 2 lines
 Karel Zak  <[email protected]>
 http://karelzak.blogspot.com