[Solved] Unable to mount ext4 partition read/write

[2bdkid]

I just installed Gentoo on my laptop and while booting an error message comes up saying it is unable to mount my root ext4 partition read/write, I can read from it but I cannot write.

I looked through some older threads and they said to enable CONFIG_LBDAF in the kernel but this only applies to x86, not amd64 like my laptop. It does mount just fine in the installation media so it much me a missing kernel option.

I don't know what commands to use to solve this myself so any help would be appreciated. And also bear with me, it'll be hard getting stuff of computer with only CLI lol.

[DONAHUE]

boot, run

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mount -o remount,rw /

not a fix but may restore capability while fixing. not having the following items has at times been reported as a cause of the reported problem.

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grep -i "CONFIG_DEVTMPFS=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_DEVTMPFS=y

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grep -i "CONFIG_DEVTMPFS_MOUNT=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_DEVTMPFS_MOUNT=y

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grep -i "CONFIG_FSNOTIFY=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_FSNOTIFY=y

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grep -i "CONFIG_DNOTIFY=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_DNOTIFY=y

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grep -i "CONFIG_INOTIFY_USER=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_INOTIFY_USER=y

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grep -i "CONFIG_NET=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_NET=y

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grep -i "CONFIG_PROC_FS=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_PROC_FS=y

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grep -i "CONFIG_SIGNALFD=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_SIGNALFD=y

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grep -i "CONFIG_SYSFS=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_SYSFS=y

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grep -i "CONFIG_SYSFS_DEPRECATED is not set" /mnt/gentoo/usr/src/linux/.config

# CONFIG_SYSFS_DEPRECATED is not set

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grep -i 'CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"' /mnt/gentoo/usr/src/linux/.config

CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"

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grep -i "CONFIG_BLK_DEV_BSG=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_BLK_DEV_BSG=y

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grep -i "CONFIG_TMPFS=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_TMPFS=y

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grep -i "CONFIG_TMPFS_POSIX_ACL=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_TMPFS_POSIX_ACL=y

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grep -i "CONFIG_TMPFS_XATTR=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_TMPFS_XATTR=y

[2bdkid]

boot, run

Code: Select all

mount -o remount,rw /

not a fix but may restore capability while fixing. not having the following items has at times been reported as a cause of the reported problem.

Code: Select all

grep -i "CONFIG_DEVTMPFS=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_DEVTMPFS=y

Code: Select all

grep -i "CONFIG_DEVTMPFS_MOUNT=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_DEVTMPFS_MOUNT=y

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grep -i "CONFIG_FSNOTIFY=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_FSNOTIFY=y

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grep -i "CONFIG_DNOTIFY=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_DNOTIFY=y

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grep -i "CONFIG_INOTIFY_USER=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_INOTIFY_USER=y

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grep -i "CONFIG_NET=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_NET=y

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grep -i "CONFIG_PROC_FS=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_PROC_FS=y

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grep -i "CONFIG_SIGNALFD=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_SIGNALFD=y

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grep -i "CONFIG_SYSFS=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_SYSFS=y

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grep -i "CONFIG_SYSFS_DEPRECATED is not set" /mnt/gentoo/usr/src/linux/.config

# CONFIG_SYSFS_DEPRECATED is not set

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grep -i 'CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"' /mnt/gentoo/usr/src/linux/.config

CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"

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grep -i "CONFIG_BLK_DEV_BSG=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_BLK_DEV_BSG=y

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grep -i "CONFIG_TMPFS=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_TMPFS=y

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grep -i "CONFIG_TMPFS_POSIX_ACL=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_TMPFS_POSIX_ACL=y

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grep -i "CONFIG_TMPFS_XATTR=y" /mnt/gentoo/usr/src/linux/.config

CONFIG_TMPFS_XATTR=y

Ok I tried enabling all of these and it didn't fix it. I also tried using rootfstype=ext4 in grub and it didn't work.

When booting it says "mount -t ext4 -o ro" Would this be a problem with my fstab?

For my root partition I just have <opts> set at default.

[2bdkid]

Ok I just tried using default,noatime,rw in my fstab and that didn't fix anything.

[2bdkid]

mount -o remount,rw / gives me "mount: / not mounted or bad option"

[NeddySeagoon]

2bdkid,

Is your / listed in /dev

Does it shaw in the output of mount and df.

root is always mounted read only to start with so rootfsck can be run.
When that succeeds. root is remounted rw.
If it fails, you should see something in dmesg.

ext2 and ext3 can mount some ext4 fs, depending on the ext4 options in use.
In some cases, as read only. df and/or mount will show that.

As a throw away snippet, the root entry in fstab is not used to mount root.
That would be chicken and egg, since root has to be mounted to read /etc/fstab.
However, /etc/fstab is used to know the root filesystem type for rootfsck.

I suspect that rootfsck is failing for some reason, so root remains read only.

Is /etc/mtab a real file or a symlink?
For openrc, both work, systemd users must have the symlink. This is the table of mounted filesystems and will be consulted by -o remount

[2bdkid]

2bdkid,

Is your / listed in /dev

Does it shaw in the output of mount and df.

root is always mounted read only to start with so rootfsck can be run.
When that succeeds. root is remounted rw.
If it fails, you should see something in dmesg.

ext2 and ext3 can mount some ext4 fs, depending on the ext4 options in use.
In some cases, as read only. df and/or mount will show that.

As a throw away snippet, the root entry in fstab is not used to mount root.
That would be chicken and egg, since root has to be mounted to read /etc/fstab.
However, /etc/fstab is used to know the root filesystem type for rootfsck.

I suspect that rootfsck is failing for some reason, so root remains read only.

Is /etc/mtab a real file or a symlink?
For openrc, both work, systemd users must have the symlink. This is the table of mounted filesystems and will be consulted by -o remount

Yes I can see sda3 in /dev

df says it cannot read table of mounted file systems

/etc/mtab is just a file, I'm using openrc

Here is dmesg: https://dl.dropboxusercontent.com/u/74532228/dmesg.txt

Would it be best to reinstall and have a seperate boot partition?

[2bdkid]

I have a feeling it's because I need a boot partition. I'm just going to reinstall, I wont lose anything.

[2bdkid]

Well I just reinstalled and added a boot partition. Everything is working fine now.

[NeddySeagoon]

2bdkid,

By reinstalling, you have lost a learning opportunity.

Your dmesg says

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[   10.945769] EXT4-fs (sda3): Unrecognized mount option "default" or missing value

which tells that your /etc/fstab was incorrect. Reinstalling allowed you an opportunity to not make that mistake again. A /boot partition is needed only if
a) the BIOS cannot read the entire HDD.
b) root on raid/LVM/encrypted or other less common installs.

Your dmesg also says

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 [10841.343765] FAT-fs (sdc1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.

You probably removed tho volume without unmounting it first. Thats a very bad thing.

[DONAHUE]

dmesg said

EXT4-fs (sda3): Unrecognized mount option "default" or missing value

correct spelling is defaults, apparently got corrected during the reinstall

[2bdkid]

I see what you mean. I guess I missed that in dmesg.