Unable to use ext4 as root fs
Hi.
I am trying to move my PC from
ext3 to ext4, and so far I can't
get it to boot. I am getting this:
---
EXT3-fs: sda3: couldn't mount because of unsupported optional features (240).
---
Google reveals that this is normal, and the next thing would be the ext4 mount, but this doesn't happen. The current git kernel just locks up tight after that message. NMI watchdog doesn't do anything. The Fedora kernel doesn't lock up, the keyboard works, you can Ctrl-Alt-Del, but nothing happens, ext4 does not mount.
I know that ext4 support is compilled in (builtin, not a module), because this very kernel mounts ext4 fine if I boot from ext3 root fs.
Now, with the lack of the usual "unable to mount root, kernel panic", I am starting to suspect a bug somewhere. Can someone please give me the hint about what have to be done to boot from ext4? Or, in case there is nothing special to do, where should I start sticking printk's to get that somehow debugged?
Quoted 8 lines · Stas Sergeev
Hi.
I am trying to move my PC from
ext3 to ext4, and so far I can't
get it to boot. I am getting this:
---
EXT3-fs: sda3: couldn't mount because of unsupported optional features (240).
---
Depending on your distribution, you may need to fix /etc/fstab to reflect ext4 as the fs type, or remake your initrd/initramfs - something in your boot process is trying to mount it explicitly as ext3 ("-o ext3"), which will of course fail.
-Eric
Quoted 27 lines
Google reveals that this is normal, and the next thing would be the ext4 mount, but this doesn't happen. The current git kernel just locks up tight after that message. NMI watchdog doesn't do anything. The Fedora kernel doesn't lock up, the keyboard works, you can Ctrl-Alt-Del, but nothing happens, ext4 does not mount.
I know that ext4 support is compilled in (builtin, not a module), because this very kernel mounts ext4 fine if I boot from ext3 root fs.
Now, with the lack of the usual "unable to mount root, kernel panic", I am starting to suspect a bug somewhere. Can someone please give me the hint about what have to be done to boot from ext4? Or, in case there is nothing special to do, where should I start sticking printk's to get that somehow debugged?Signature · 3 lines
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Quoted 8 lines · Eric Sandeen
Quoted 4 lines
---
EXT3-fs: sda3: couldn't mount because of unsupported optional features (240).
---Depending on your distribution, you may need to fix
/etc/fstabto reflect ext4 as the fs type, or remake your initrd/initramfs - something in your boot process is trying to mount it explicitly as ext3 ("-o ext3"), which will of course fail.
Thanks Eric, rebuilding initrd worked! It is still quite annoying that something in the initrd makes the latest git kernel to lock up hard after the mount failure (and not for the Fedora kernel), but this is probably unrelated to ext4... Thanks for your help!