ext4

Is there any e4crypt kernel side documentation?

Is there any e4crypt kernel side documentation? I’m trying to understand e4crypt and fscrypt, and also how they differ. But it is hard to find documentation on e4crypt other than the command line tool man page and some old tutorials. Is there any documentation on how the kernel side of things work? I’m mainly interested …

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Why a filesystem is unmounted but still in use?

Why a filesystem is unmounted but still in use? I was using ext4 filesystems for a long time, and it’s the first time I see a weird behavior of ext4 filesystem. There is ext4 filesystem in /dev/dm-2 An I/O error happened in the underlying device, and the filesystem was remounted read-only. It is fine and …

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How do I rescue an encrypted LUKS partition after failed shrink

How do I rescue an encrypted LUKS partition after failed shrink I had an encrypted ext4 partition on a Samsung T7 1TB USB drive. It was LUKS (I believe this may be called a LUKS container?) The partition was 850GB. It had about 130GB in use. I also had an unencrypted 100GB NTFS partition and …

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How does EXT4 handle sudden lack of space in the underlying storage?

How does EXT4 handle sudden lack of space in the underlying storage? Usually, block device drivers report correct size of the device, and it is possible to actually use all the "available" blocks. So, the filesystem knows how much it can write to such device in prior.But in some special cases, like it is with …

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Debian file corruption bug possible without reboot after unattended kernel update?

Debian file corruption bug possible without reboot after unattended kernel update? Today I learned that there had been a faulty Debian kernel version which caused ext4 data corruption (bug 1057843) in December 2023. Searching through the /var/log/aptitude and /var/log/apt logs, I noticed that the faulty kernel version was installed for one full day by /usr/bin/unattended-upgrade …

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What can cause “multiply claimed blocks” on an ext4 drive?

What can cause “multiply claimed blocks” on an ext4 drive? “Multiply claimed blocks” is an error reported by fsck when blocks appear to belong to more than one file. This causes data corruption since both files change when one of the files are written. But what can be the original causes of multiply claimed blocks? …

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Are there downsides to enabling the "inline data" feature of EXT4?

Are there downsides to enabling the "inline data" feature of EXT4? I just read about the "inline data" feature in EXT4, and more specifically about that answer on how to enable it. What are the reasons why this feature isn’t enabled by default in EXT4 ? I guess it’s to keep the FS compatible with …

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Scan online EXT4 using LVM snapshot?

Scan online EXT4 using LVM snapshot? Can you make a trustworthy EXT4 filesystem-scan of an online filesystem, e.g. root, by taking a LVM snapshot and then do a scan on the snapshot, something like: Make a snapshot: lvcreate –snapshot –size 1G –name lv_root_SS –chunksize 4k /dev/VG1/lv_root EXT4 scan: e2fsck -f /dev/dm-3 (device-name of the new …

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videos from non-linux partition dont't play

videos from non-linux partition don't play I installed linux dual boot with windows, now I can’t play any videos from another mounted partition. I should also mention that only videos have this problem and I can open pictures, documents, music, … with no problem. Also the problem is not video codecs, If I copy and …

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In EXT4, are "extent" and "block group" the same thing?

In EXT4, are "extent" and "block group" the same thing? TLDR; In EXT4 terminology, are "block groups" and "extents" the same thing ? [EDIT] The suggested What do "extents" feature do in ext4 filesystem in linux? discussion doesn’t answer that question. While it explains clearly what "extents" are, it doesn’t talk about "block groups", and …

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First 32GB of a 4TB ext4 filesystem overwritten. How to recover?

First 32GB of a 4TB ext4 filesystem overwritten. How to recover? Due to an accident specifying a block device, the first 32GB of a 4TB ext4 filesystem on a SATA disk was overwritten by the dd command with the contents of a USB flash drive. fdisk -l /dev/sda reports the following: Disk /dev/sda: 3.7 TiB, …

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Is there some universally recommended Reserved block count (for root) for large Ext4 drives?

Is there some universally recommended Reserved block count (for root) for large Ext4 drives? By the following question: Is there some universally recommended Reserved block count (for root) for large Ext4 drives? I specifically mean the following: Let us consider (almost) everyone has a rather large root drive (partition) nowadays. Let us consider for example …

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Is using the SysRQ Emergency Remount an acceptable way to clone hard disk?

Is using the SysRQ Emergency Remount an acceptable way to clone hard disk? I’m using Linux (Ubuntu) and I was told that I can use the method described below to clone the system’s hard drive to another one – to plug into a new machine. (Without booting from a Live CD) It assumes that the …

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Recovering an ext4 partition

Recovering an ext4 partition I have an external drive with an ext4 partition /dev/sda1 I use for my local borg backups. It is simply plugged in via usb port, and, mounted with an fstab generated systemd automount entry. I ran a backup yesterday in the evening without any errors, and this morning, I plugged it …

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Minimalistic ext4 filesystem without journal and other advanced features

Minimalistic ext4 filesystem without journal and other advanced features I have a small "rescue" system (16 MB) that I boot into RAM as ramdisk. The initrd disk that I am preparing needs to be formatted. I think ext4 will do fine, but obviously, it doesn’t make any sense to use journal or other advanced ext4 features. …

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How to enable data=journal ext4 fs mode?

How to enable data=journal ext4 fs mode? Preface (my 1st attempt ended badly): Fstab adding data=journal crashed my Linux' ext4 upon boot, how to fix? I can’t find some reliable step-by-step instructions on How to enable data=journal ext4 fs mode? (It is my root file system.) Can anyone help? Thank you! OS: Linux Mint 21.1 …

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Fstab adding data=journal crashed my Linux' ext4 upon boot, how to fix?

Fstab adding data=journal crashed my Linux' ext4 upon boot, how to fix? I changed my /etc/fstab from: UUID=f1fc7345-be7a-4c6b-9559-fc6e2d445bfa / ext4 errors=remount-ro 0 1 UUID=4966-E925 /boot/efi vfat umask=0077 0 1 to this: UUID=f1fc7345-be7a-4c6b-9559-fc6e2d445bfa / ext4 data=journal,errors=remount-ro 0 1 UUID=4966-E925 /boot/efi vfat umask=0077 0 1 Effectively adding data=journal, before errors=remount-ro option. The reasoning was this computer is …

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