[opensuse-factory] Proposal: removal of /dev/root symlink
Hi all, I'd like to know if there would be strong objections to this proposal. The main reason is that this symlink is not be reliable in all cases since direct relation between the rootfs and the backing block device is not always possible (think BTRFS). It's been removed since a while now in the other distros and I don't think any tool relies on it these days. For the few users who would want to continue using the symlink the relevant udev rule could still be copied in /etc/udev/rules.d The removal would take effect during the upgrade to v233, which should happen in a couple of weeks if nothing goes wrong. Thanks. -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
Franck Bui wrote:... So what would "df /" show for the device? The real device? -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
On Tue, Mar 21, L.A. Walsh wrote:
Franck Bui wrote:...
So what would "df /" show for the device?
The real device?
I would assume the same as today: # df / Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda3 41946112 11222272 30584896 27% / -- Thorsten Kukuk, Distinguished Engineer, Senior Architect SLES & CaaSP SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nuernberg, Germany GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
Thorsten Kukuk wrote:
I would assume the same as today: # df / Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda3 41946112 11222272 30584896 27% /
--- Same as today?: Ishtar:/> df . Filesystem Size Used Avail Use% Mounted on /dev/root 12G 5.8G 6.3G 48% / Ishtar:/> ll /dev/root lrwxrwxrwx 1 4 Mar 3 08:13 /dev/root -> sdc1 *puzzled look*: Good, good, I wouldn't want there to be any confusion... Um... What is /dev/sda3? I was told that it was not possible to show the real root one booted from and that /dev/root was necessary because of some excuse that didn't make technical sense to me and that it was required by the new 'bootd' (Sysd). /etc/mtab points to /proc/self/mounts, and in there, I see: Ishtar:/> grep root /proc/self/mounts /dev/root / xfs rw,relatime,attr2,inode64,noquota 0 0 /dev/root /tmp xfs rw,relatime,attr2,inode64,noquota 0 0 /dev/root /tmp xfs rw,relatime,attr2,inode64,noquota 0 0 /dev/root /tmp xfs rw,relatime,attr2,inode64,noquota 0 0 ( which has little to do with my /etc/fstab: Ishtar:/> grep /root /etc/fstab Ishtar:/> grep -P '\s/\s' /etc/fstab /dev/sdc1 / xfs nodiratime,swalloc,largeio,logbsize=256k,allocsize=64k 1 1 ) i.e. where my mount to root is what is showing as the destination of /dev/root. so when did /dev/root become unnecessary? Not that I'm too upset about it, but I don't suppose anyone wants to explain why we were told it was necessary, when it wasn't? Sigh... -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
On Wed, Mar 22, L A Walsh wrote:
Ishtar:/> df . Filesystem Size Used Avail Use% Mounted on /dev/root 12G 5.8G 6.3G 48% / Ishtar:/> ll /dev/root lrwxrwxrwx 1 4 Mar 3 08:13 /dev/root -> sdc1
*puzzled look*: Good, good, I wouldn't want there to be any confusion... Um...
# LANG=C ll /dev/root ls: cannot access '/dev/root': No such file or directory The question is more, in which case is /dev/root created? I don't have this symlink, neither on openSUSE Tumbleweed nor on my SLES installations.
What is /dev/sda3?
My root device.
I was told that it was not possible to show the real root one booted from and that /dev/root was necessary because of some excuse that didn't make technical sense to me and that it was required by the new 'bootd' (Sysd).
Which seems really be a lame excuse, because there must be a way to find out the real root device, else the link /dev/root couldn't be created, too. Between, df is reading the root device from /proc/self/mountinfo. Thorsten -- Thorsten Kukuk, Distinguished Engineer, Senior Architect SLES & CaaSP SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nuernberg, Germany GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 2017-03-22 21:04, Thorsten Kukuk wrote:
# LANG=C ll /dev/root ls: cannot access '/dev/root': No such file or directory
The question is more, in which case is /dev/root created?
I don't have this symlink, neither on openSUSE Tumbleweed nor on my SLES installations.
cer@minas-tirith:~> LANG=C ll /dev/root lrwxrwxrwx 1 root root 4 Mar 14 20:05 /dev/root -> sda7 cer@minas-tirith:~> cer@Isengard:~> LANG=C ll /dev/root lrwxrwxrwx 1 root root 4 Feb 6 04:56 /dev/root -> sda4 cer@Isengard:~> Both Leap 42.2 system. The first one upgraded from 13.1 and older, the second freshly installed. - -- Cheers / Saludos, Carlos E. R. (from 42.2 x86_64 "Malachite" (Minas Tirith)) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iF4EAREIAAYFAljTGVkACgkQja8UbcUWM1zs0gD/V2Owbpbeg5BUmhU2Rc5CcNcm ewHX2BmnAt1Sxd6Iwo4A/2jhHOABP8dbgS6nBf4QP99jqiXut+edM/9KODq3btT0 =BoVn -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
Carlos E. R. wrote:
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256
On 2017-03-22 21:04, Thorsten Kukuk wrote:
# LANG=C ll /dev/root ls: cannot access '/dev/root': No such file or directory
The question is more, in which case is /dev/root created?
I don't have this symlink, neither on openSUSE Tumbleweed nor on my SLES installations.
cer@minas-tirith:~> LANG=C ll /dev/root lrwxrwxrwx 1 root root 4 Mar 14 20:05 /dev/root -> sda7 cer@minas-tirith:~>
cer@Isengard:~> LANG=C ll /dev/root lrwxrwxrwx 1 root root 4 Feb 6 04:56 /dev/root -> sda4 cer@Isengard:~>
Both Leap 42.2 system. The first one upgraded from 13.1 and older, the second freshly installed.
Yep, I have the same on Leap422. -- Per Jessen, Zürich (8.6°C) http://www.dns24.ch/ - your free DNS host, made in Switzerland. -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
On 03/23/2017 09:48 AM, Per Jessen wrote:
Both Leap 42.2 system. The first one upgraded from 13.1 and older, the second freshly installed.
Yep, I have the same on Leap422.
Probably because your rootfs is ext4. But the point is that no one should rely on this symlink these days. You can try too boot with the following option appended to the kernel command line: "systemd.mask=systemd-udev-root-symlink.service" The symlink should not be created anymore and your system should work flawlessly. -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
Franck Bui wrote:
On 03/23/2017 09:48 AM, Per Jessen wrote:
Both Leap 42.2 system. The first one upgraded from 13.1 and older, the second freshly installed. Yep, I have the same on Leap422.
Probably because your rootfs is ext4.
It's jfs actually.
But the point is that no one should rely on this symlink these days. You can try too boot with the following option appended to the kernel command line: "systemd.mask=systemd-udev-root-symlink.service"
The symlink should not be created anymore and your system should work flawlessly.
I'll try that. /Per -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
Per Jessen wrote:
Franck Bui wrote:
But the point is that no one should rely on this symlink these days. You can try too boot with the following option appended to the kernel command line: "systemd.mask=systemd-udev-root-symlink.service"
The symlink should not be created anymore and your system should work flawlessly.
I'll try that.
It works fine without /dev/root. -- Per Jessen, Zürich (14.6°C) http://www.cloudsuisse.com/ - your owncloud, hosted in Switzerland. -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 2017-03-23 11:03, Franck Bui wrote:
On 03/23/2017 09:48 AM, Per Jessen wrote:
Both Leap 42.2 system. The first one upgraded from 13.1 and older, the second freshly installed.
Yep, I have the same on Leap422.
Probably because your rootfs is ext4.
In my case, yes, it is. But not in Per's.
But the point is that no one should rely on this symlink these days. You can try too boot with the following option appended to the kernel command line: "systemd.mask=systemd-udev-root-symlink.service"
Well, I don't know what creates it nor what for, but I worry that something uses it and will fail if removed. I can't try now to reboot with that option, sorry. Maybe later. - -- Cheers / Saludos, Carlos E. R. (from 42.2 x86_64 "Malachite" (Minas Tirith)) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iF4EAREIAAYFAljTu2cACgkQja8UbcUWM1y4iAD/ZKcNituDHimcE4GicxBVCY2T +K4Lmj8zbN6ga32MfA8A/1cZhlQU3WQFrAdU2GpSL8bkZZ0OBNO2bq15Nc1ut7YK =hL5w -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
On Thu, Mar 23, Carlos E. R. wrote:
Well, I don't know what creates it nor what for, but I worry that something uses it and will fail if removed.
Since we don't create that symlink in case you use btrfs, and nothing broke until now, you can be sure that this will not break anything which is important. Else we would have seen quite a lot reports. Thorsten -- Thorsten Kukuk, Distinguished Engineer, Senior Architect SLES & CaaSP SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nuernberg, Germany GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 2017-03-23 14:46, Thorsten Kukuk wrote:
On Thu, Mar 23, Carlos E. R. wrote:
Well, I don't know what creates it nor what for, but I worry that something uses it and will fail if removed.
Since we don't create that symlink in case you use btrfs, and nothing broke until now, you can be sure that this will not break anything which is important. Else we would have seen quite a lot reports.
Ah, good point, thank you! - -- Cheers / Saludos, Carlos E. R. (from 42.2 x86_64 "Malachite" (Minas Tirith)) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iF4EAREIAAYFAljT1x4ACgkQja8UbcUWM1xi8QEAhP3mEtBANkjNzuTmlIPW9QSZ OBQ+ar1feEpc/SvmQ50A/2eBdUPiNTJYhnROGopffu3yZuZfiQnqx/0V+FR10IBo =BVtY -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
On 03/22/2017 09:04 PM, Thorsten Kukuk wrote:
The question is more, in which case is /dev/root created?
Basically if you're using BTRFS for your rootfs the /dev/root symlink won't be created because there's not direct mapping between your root partition and the backing block dev. -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
Am Thu, 23 Mar 2017 10:40:51 +0100
schrieb Franck Bui
Basically if you're using BTRFS for your rootfs the /dev/root symlink won't be created because there's not direct mapping between your root partition and the backing block dev.
Why is that? /dev/root points to an ordinary block device node, and in case of btrfs the blockdevice has yet another concept of "container" which is referenced by the subvolume value. Olaf
On 03/22/2017 08:16 PM, L A Walsh wrote:
I was told that it was not possible to show the real root one booted from and that /dev/root was necessary because of some excuse that didn't make technical sense to me and that it was required by the new 'bootd' (Sysd).
I don't think systemd-boot (aka gummyboot) has any use of /dev/root. If you have any link to share that would help to clarify.
/etc/mtab points to /proc/self/mounts, and in there, I see:
Ishtar:/> grep root /proc/self/mounts /dev/root / xfs rw,relatime,attr2,inode64,noquota 0 0 /dev/root /tmp xfs rw,relatime,attr2,inode64,noquota 0 0 /dev/root /tmp xfs rw,relatime,attr2,inode64,noquota 0 0 /dev/root /tmp xfs rw,relatime,attr2,inode64,noquota 0 0
( which has little to do with my /etc/fstab: Ishtar:/> grep /root /etc/fstab
Weird. Could you show the content of /proc/cmdline ? Maybe "grep -R /dev/root /etc" could show more... -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
Franck Bui wrote:
I don't think systemd-boot (aka gummyboot) has any use of /dev/root. If you have any link to share that would help to clarify. ===
It would have been from some time back (maybe when 13.1 was being released?) I wasn't real happy about it, so haven't worked on keeping it up-to-date or working...
Could you show the content of /proc/cmdline ?
(I boot a vanilla kernel config'd for my HW from a RAID5 disk set): # cat /proc/cmdline reboot=bios BOOT_IMAGE=4101-Isht-Van rw root=/dev/sdc1 root=/dev/sdc1 nomodeset LINES=43 COLUMNS=132 rw showopts console=ttyS0,115200n8 console=tty0 elevator=deadline pcie_ports=native reboot=bios printk.time=1
Maybe "grep -R /dev/root /etc" could show more...
I see a file that indicates it _might_ be some 'udev' rule (that I likely don't need)... /etc/rc.d/boot.udev: # create /dev/root symlink with dynamic rule FWIW, I don't think it is likely to cause a problem on my system, and I have no problems with it going away, I just remember being told how it "had to be", so was a bit bemused/surprised to hear it was going away. Another one of those *mandatory* flash-in-the-pan requirements, apparently. -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org
participants (7)
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Carlos E. R. -
Franck Bui -
L A Walsh -
L.A. Walsh
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Olaf Hering -
Per Jessen -
Thorsten Kukuk