Questions tagged [ext4]

ext4 (fourth extended filesystem) is a journalling file system for Linux, developed as the successor to ext3. Use this tag for question that are ext4 specific, generic file system related questions should use tag [filesystem]

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460 views

When do logical partitions happen to need 1MB gap at each side in gparted?

I had a similar problem with this one: Why can't I create a logical partition with gparted?, where a logical partition cannot be created/formatted. Only in my case I was in a live session and it still ...
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5k views

Grub rescue after corrupted hard-drive (“read-only filesystem”)

I run xubuntu 12.04 alongside a NTFS storage partition and a windows 8 partition. I moved my MySQL data directory off the xubuntu (ext4) partition, onto the NTFS partition, and did an import of a ...
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No access to symlink folder on NTFS partition

I am using an NTFS parition for storing data I like to access both from Ubuntu and Windows 7. On my Ubuntu HOME partition, I like to link the folder Assets in order to access it from an application ...
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420 views

Trouble mounting 5Tb external USB device

I purchased a Seagate Backup Plus 5 TB USB 3.0 Portable 2.5" drive as I've recently maxed out the 1TB drive I have connected to my RPi2 running ArchLinuxARM and serving up music around the home (...
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543 views

What is the most recent technique to implement quotas?

Is the quota approach still in use? To limit the usage of disk space and/or the concurrency between users. Quota works with aquota.user files in the concerned directories AND some settings in /etc/...
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1answer
275 views

Ext4: I/O errors on a clean external drive

So I've an external Seagate hard disk that I used to mount on my Mac through Paragon ExtFS. For some unknown reason it stopped to mount on my Mac due to I/O errors - I may have removed the drive ...
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1k views

jbd2 journal constant i/o

iotop reports a constant i/o about 3% of [jbd2/vda1-8], I think this is the journal manager for ext4. my fstab is: UUID=X / ext4 defaults,noatime,nodiratime 1 1 tmpfs /dev/shm ...
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95 views

Filesystem got corrupted overnight

OS: xUbuntu 18.04 LTS. I have my OS installed on 256GB SSD: /boot on ext2 / on ext4 (encrypted) That works fine. I have installed the second 1TB HDD recently for storage and backup. Model: WDC ...
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349 views

ext4 jbd2 and I/O priority

I want to delete a huge directory with over 6 million files across over 4000 directories, totaling about 26GB of data. As I knew this was going to take a while I used ionice to set the I/O priority ...
3
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1answer
249 views

How does Linux make sure to reclaim useless “buffers”, from caching the ext4 journal writes, before anything else (e.g. before swapping at all)

My laptop tends to run with about 256MB counted as "Buffers" - in /proc/meminfo and free -w -h - out of about 8GB of RAM. I'm interested in memory usage. I sometimes get into trouble using too much. ...
3
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1answer
271 views

lvmcache and ext4 data=journal => overkill?

We are running lvmcache (24TB raid5 hdd data, 64GB raid1 ssd cache+meta) and we are using external journal with data=journal for the ext4 fs on that raid5 and have the journal on the same ssd raid1 (...
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561 views

ext4 mount: mount /dev/mmcblk0p2 on /SD failed: File exists?

If I try mounting the ext4 file system of /dev/mmcblk0p2 into the blank directories I just created: /SD and also /mnt/SD, then the command line answers with: mount: mount /dev/mmcblk0p2 on /SD failed:...
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956 views

How to stop jbd2 on unmounted filesystem

I need to resize2fs the root partition of an embedded device. Since it doesn't have an alternate boot option, I used an tmpfs, moved and restated everything until I finally was able to umount /dev/...
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77 views

Undeleteable 33GiB file on a 4GiB USB-Stick. fsck says “clean”, Error: “Operation not permitted”

I successfully installed a live debian 8.x on a 4G thumb-drive, like many times before. However, this time there is a 33GiB tee.1.gz file in /usr/share/man/man1/, which is much larger than a normal ...
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1k views

Difference in space reserved for inodes in ext4 and XFS partitions

I am formatting a couple of 60G Logical Volumes (vg01-logs and vg01-monitoring) in one of our servers. These partitions will hold a large number of small files, so I want them with more than the ...
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722 views

ext4 inodes in use for files that are missing

Executive summary: Every tool I've tried confirms lots of inodes in use on this ext4 partition Every tool I've tried shows me that there are no files on the partition It's not files held open and it'...
3
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1answer
822 views

ext3 vs ext4 - same disk size, less usable disk space under ext4 comparing to ext3. why?

Files copied from ext3 filesystem do not fit on same size ext4 filesystem. How to reproduce: create two 1GB files, setup loop device for each, create filesystem one ext3, one ext4, mount, rsync ...
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1k views

EXT4 Journaling - Problem

Basically my root (/) ext4 partition keeps being mounted as read-only when I apply internal journaling feature. I understand that this should be default, but today I had been trying to apply external ...
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102 views

Mapping a physical sector to a filename

I just finished using ddrescue to recover the contents of a failing hard drive. It was able to recover everything but two sectors. How do I figure out which files (if any) occupied those sectors? ...
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ext4 - An entire directory disappeared?

Okay, this has me totally stumped. Background: I'm working on a cryptanalysis homework, trying to break a vigenere cipher with a 26 character key (a shuffled alphabet). Even though there are some 403 ...
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193 views

Problems with file system

I created a partition with EXT4 file system and when I'm writing in this partition frequently the Kernel return the following error: Jan 01 01:17:54 infobuffer360 kernel: r7:c0561280 Jan 01 01:17:54 ...
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170 views

Have I destroyed data on drive?

I stupidly ran the following command on an external ext4 USB disk, typing /dev/sdb instead of /dev/sda which was the new disk I was setting up: dd if=/dev/zero of=/dev/sda bs=512 count=100 These ...
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288 views

How to limit ext4 filenames to only those filenames legal in FAT?

The ext4 filesystem allows some characters that FAT does not allow, such as :. This has caused me much grief in the past when trying to move files, especially as KDE will delete such files instead ...
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29 views

Are released blocks logged in the journal for ext4?

Suppose we have a simple case: ext4 file system with journaling a single file named file, which has no other hard links the inode for file has associated with it only 1 data block My understanding ...
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72 views

Recover accidentally deleted custom files

I accidentally deleted important custom (not known-or-commercial) files from my scientific researches on image processing. I created the files by collecting raw digital signals from an image sensor. ...
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198 views

processes hanging when trying to access a file

I'm running Ubuntu 16.04.5 and the ext4 filesystem, and I have a file which causes processes to hang when they read it. For example: $ cat /path/to/file.txt and then from a separate terminal: $ ...
2
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1answer
105 views

How to recover when ext4 superblock's inode count is reset to 0

We tried to resize a 15TB ext4 partition to 16TB and accidentally managed to hit an old (and fixed in newer releases) off-by-one bug of ext4_resize_fs() which causes inode count to reset to 0 thanks ...
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232 views

debugfs occasionally fails to read inode data

I need to get date and time when a file was created. The file is stored at ext4 filesystem so the information is available in the i-node and I use debugfs to read this information: # debugfs -R "stat ...
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1k views

EXT4 app2sd link2sd partition repair with bad superblock . Partition cannot be mounted on Android but will mount RW w/ su on Linux Live

I have a 128gb micro sd formatted as ext4 10gb for app2sd 2nd ext4 partition ( p2 ) on my Android 6 phone . All my apps ( 80%) stay on that ext4 partition . Now app2sd cant load this partition - "...
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169 views

Are there any known ext4 issues that could randomly cause files to become zero-bytes in length?

My company produces Android devices running Linux 3.4 and we have seen that sometimes but rarely a file on the ext4 emmc file system will suddenly become zero-length. Normally I would suspect an ...
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137 views

Looking for 4 TB cross-platform filesystem for standalone disk

This is partially coming from https://superuser.com/questions/227664/cross-platform-file-system-open-source/1274486#1274486 I have been looking for a filesystem which is supported on both platforms. ...
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118 views

How does the kernel decide to make an SD card filesystem read-only?

I understand that low-level NAND flash can effectively wear out and that an SD card controller (residing on the card itself) is responsible for managing the flash and exposing a comparatively simple ...
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202 views

Cannot mount SD card after hard shutdown

I have an SD card in my raspberry PI, on which I pulled the power. Now, I cannot boot from it, or even read it from my (Fedora) laptop. When running fsck I get this error: [bf@localhost ~]$ sudo ...
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654 views

Mount ext4 formatted mircosd on Nvidia Shield TV

I have a rooted Shield TV but I can't figure out how to mount the microsd card. I see that the file system is supported but I don't see where the device is listed. Usually I would look for mmcblk or ...
2
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1answer
221 views

Sizing a disk image/filesystem to hold exactly a certain set of files with near-zero free space

I need to construct, in code suitable for scripting/make/automation, a disk image (two partitions, a FAT filesystem and an ext4 filesystem, for UEFI/Syslinux USB Linux booting [OS installer], which ...
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0answers
316 views

Ext4-Error: Bit already cleared for inode

System: Debian Wheezy Kernel 3.11.6 Atmel SAM9x25 Mono 3.2.8 SD card with ext4 partition I got following message error when I booted my mono application: root@net-231:/opt/programm# [ 6061.078125] ...
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1answer
82 views

Register callback for newly inserted disk?

I was wondering if there was a way to register a callback with the system so that when a user attached an external drive my callback is called and I can then proceed to manually mount the disk. What ...
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2k views

ext4 & jbd2 dirty metadata

I have an embedded system based on the RiotBoard, I have the main file system on the MMC set as read-only, and an 8gb usb flash drive for writeable storage. rootfs is debian, linux kernel version 4.3....
2
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1answer
161 views

Any way to help “visualize” the superblock, filesystem, group descriptors, etc

I've been reading a lot about filesystems, trying to learn all I can in depth, but I'm having trouble really visualizing some of it, especially when it comes to things like the superblock, group ...
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97 views

How do distribution installers avoid ext2/3/4 initialization?

When I format a volume with ext4, I have two options regarding initialization. I can either use lazy_itable_init=1 (the default setting) to delay initialization until after the volume is first mounted,...
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1k views

Understanding ext4/jbd2 transactions

I'm trying to debug a bit of trouble I'm having with I/O latency on a system using ext4, but I'm a bit stumped in that I don't understand its journalling as well as I'd like to. What I'm wondering in ...
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1k views

Size Range of ext4 Filesystem Journal

The minimum and maximum sizes respectively for the ext3 filesystem journal are 1,024 blocks and 102,400 blocks. Similarly — what are the minimum and maximum sizes for the journal on an ext4 filesystem?...
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Find duplicity files after using PhotoRec

I've partly formatted a disc where my duplicity files was stored. I have used PhotoRec to recover the files but now they're all unsorted and without the correct filename. I have the files separated by ...
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0answers
722 views

CentOS 5.6 expand ext4 partition , have steps but parted shows as ext3

I have a Adaptec 5805 HW RAID card with a 6.3 TB RAID-6 array (partitioned via Parted GPT, all of which is formatted as ext4 on CentOS 5.6). I want to expand this to 7.5GB and from reading these are ...
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0answers
509 views

Mount from auto to manual and changing dir gives errors

I just installed Ubuntu 14.04 and am trying to mount my internal HD to a different location in the /home/username dir (auto-mount mounts it to /mnt/{uuid} ) But I ran into a problem. In Disks, when ...
2
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1answer
1k views

Best parameters for ext4 filesystem to handle virtualbox disk images

I have ext4 partition, which holds disk image files VirtualBox works with. They all are fixed-size images (i.e. files never change their size). They are defragmented as much as possible (with e4defrag)...
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1answer
1k views

How to find orphan directory entries in a ext4 disk

This comes from a long story of trying to recovering a TrueCrypt volume from a hardware failure (thanks, WD). I ended up with an unencrypted 3TB image that had the files that I want to recover. ...
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2k views

Superblock corruption on every boot

I have a Linux Mint 12 install on my laptop. Yesterday I powered it off like I always do and this morning when I started it I was greeted by an error screen. (Translated from Swedish) Fatal errors ...
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76 views

All ext4 files got deleted and the journal can't be found! Is there any way to recover it?

All of the files on my usb stick were deleted by accident (rm -r) but I'm having trouble recovering. When I try to run ext4magic it says "filesystem has no journal" and it mounts as ext2 only. I ...
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1answer
92 views

Getting sector number from inode or address_space mapping

In am trying to understand how to calculate a sector number from an inode in the ext4 filesystem. Therefore, I am reading ext4_mpage_readpages function. About the function: During a read request, if ...