Questions tagged [filesystems]
A filesystem is a way to organize and store computer files with their data.
4,011
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is stat(2) read-after-write consistent with write(2)?
man 2 write states:
POSIX requires that a read(2) that can be proved to occur after a write() has returned will return the new data. Note that not all filesystems are POSIX conforming.
In Linux, is ...
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Mount overlay and assign owner to myuser
I've an entry in /etc/fstab like this:
overlay /etc/myfolder overlay defaults,x-systemd.requires-mounts-for=/var/data,lowerdir=/etc/myfolder,upperdir=/var/data/overlay/myfolder/upper,workdir=/var/...
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Failed to run init with error: jffs2: compression type 0x06 not available
I am working on an embedded Linux system (5.10.24), and I am using jffs2 as the rootfs.
Now I changed the kernel configuration of jffs2 as follows,
# CONFIG_JFFS2_FS_WBUF_VERIFY is not set
# ...
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Is it possible for a filesystem type to be recognized differently or changed without reformatting a drive?
When running sudo fdisk -l my EXT4 formatted SamsungQVO USB SSD now identifies as APFS.
Device Start End Sectors Size Type
/dev/sda2 409640 3907029127 3906619488 1.8T Apple APFS
The ...
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14
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"Applying Directory Permissions to Files in Linux: Ownership and Access Query"
I am currently learning about Linux file permissions and have a query related to permissions on directories and files. Suppose there is a file 'x' owned by a user 'user1' and belonging to a specific ...
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btrfs subvolume quota and free space for samba share
My btrfs filesystem is mounted under /mnt/btrfs. I then created a subvolume /mnt/btrfs/sv and enabled quotas. After that I set the quota to 10G with btrfs qgroup limit -e 10G /mnt/btrfs/sv and ...
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How to merge the content of multiple subdirectories into another directory where destination contains the same directory name using a mount / union?
In the example below, exdir is a directory containing many subdirectories. The contents of each subdirectory, which are directories themselves, should be merged with /su/destdir, which already contain ...
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Can mmap be used to create a file which references memory subset of another file?
I'm interested in writing a program that can create two files, second file would be a "view" of first file and if modified, the first file would also be modified. Is this possible to do with ...
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Yocto Project for a New Board
I am trying to hunt down specifics on Yocto in regards to how to set up the filesystem before the build of poky.
I have a new board that I wanted to try Yocto on.
I have this FS so far after source oe-...
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1
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54
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sshd: Authentication refused: bad ownership or modes for directory /data
I'm trying ssh-ing into a rooted Android phone, but it gives me an error Permission denied (publickey)., and the log says Authentication refused: bad ownership or modes for directory, despite of the ...
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SSD initially mounts correctly, but disappears from lsblk after a few days
I am a Linux beginner, and am having a problem with a drive which disappears from lsblk periodically, and am stuck with how to proceed. The drive is an 240GB external USB SSD.
Mounting the Drive Works
...
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Increasing the size of the swap partition with free space partition
My hard drive has three partitions with free space that I would like to turn into swap, meaning I want to increase the size of the swap partition using the free space from these three partitions (2M + ...
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1
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108
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Equivalent of `btrfs send` and `btrfs recv` for bcachefs
I'm using a setup I consider to be rather fragile and prone to failure involving LUKS, LVM, btrfs, and bcache. I have used btrfs for a long time, and have never experienced any significant issues with ...
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How to intentionally corrupt my file system or crash its driver?
I am doing a research that involves intentionally corrupting my file system. I shouldn't be able to read or write anything to the file system after that. Therefore I am ok with crashing the drivers to ...
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none filesystem in WSL got large disk space
By running the following command, a path (/usr/lib/wsl/drivers) with none filesystem type appears:
$ df -h
Filesystem Size Used Avail Use% Mounted on
none 16G 4.0K 16G 1% /mnt/...
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1
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Why does the dd command recover a file deleted using shred?
I found the inode of a file using ls -li.
Then I found the file’s starting block on disk.
I copied the contents of the block to another directory using the dd command.
Then I shredded the file using ...
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1
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How can wildcard expansion create duplicates?
I have a directory with an absurd number of files, which makes this nigh impossible to understand by inspection. But here's the situation:
cp giant_folder/pre* myfolder
It's crunching along and ...
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2
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Why should I use `sudo` with the `passwd` command to change the password of another user?
If you look at the permission set of the passwd command, you will see this:
user@apple:~$ ls -l /bin/passwd
-rwsr-xr-x 1 root root 59976 Nov 24 2022 /bin/passwd
/bin/passwd has the SUID bit set and ...
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NFS dir permissions changed not visible
I have an nfs storage mounted at /mnt/data.
This is mounted across several VMs in the same mountpoint.
I changed the permissions of the dir from 775 to 770. The change is visible only in one VM. I did ...
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35
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2
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Why is filesystem time always some msecs behind system time in Linux?
In Linux, it seems that filesystem time is always some milliseconds behind system time, leading to inconsistencies if you want to check if a file has been modified before or after a given time in very ...
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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 ...
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1
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Does iowaitnotify close_wait guarantee the file is written completely?
Please clarify if close_write event of ionotifywait will guarantee that the file has been completely written.
The situation is a file transfer program will send a file X to a remote server Z and need ...
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0
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17
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Surprise in measuring UBIFS on NAND performance in Linux
I am working on an embedded Linux system (Linux-5.10.24), and there is a raw NAND FLASH as storage device on which UBI/UBIFS is used as file system.
Now I am trying to measure and compare the UBIFS ...
- 387
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49
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Remove write permission but keep delete permission
This is an odd one, a file in my server is written to once every boot by one of the services in it. I found out that another process (that I have no control of) keeps changing the contents, so I made ...
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1
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31
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BTRFS partition will not mount after power off
I'm running Fedora 38 on a BTRFS partition and just had to do a hard power off due to system hang. Now the system goes into emergency mode on bootup. I'm currently running the fedora live CD but the ...
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0
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30
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Data Replication Approaches for Hot Standby Architecture
I'm relatively new to the world of storage & filesystems (please forgive me if I'm not using the correct language), and I'm currently researching ways to achieve a hot standby configuration -- i.e....
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1
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resize disk partition which is used by RAID
I need to shrink the sdb4 partition, which currently occupies the entire 7TB of my sdb drive, in order to create an sdb5 partition for my application. The challenge lies in the fact that there is a ...
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1
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183
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Set default system filedialog on open and save in KDE Plasma 5
I use dolphin as my file manager. I have this behavior of my system: Whenever I open or save something using a KDE app, the dialog used is kdialog. (If you use Plasma you can trigger one using kdialog ...
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0
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40
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HDD keeps locking to read-only; Cannot isolate cause of disk errors
The problem: After running with no issues for several months, one of my HDDs will lock into read-only mode seemingly at-random when in use. This can often be fixed by cycling power to the hard drives.
...
1
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1
answer
51
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How to generate a raw UBI image with 2 UBI volumes?
I am working on an embedded Linux (kernel-5.24), where UBIFS is used as filesystem for both rootfs and user configuration data.
Now I am trying to generate one single UBI image to burn the NAND FLASH (...
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0
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23
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Big Maildir mailspool - looking for ways to improve performance
I have an extremely large Maildir which contains emails going back many years. I need to rebuild the server and would like to improve the mail storage setup.
My main problem is that backups of the ...
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1
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61
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How to build a UBIFS image to make use of the remaining space of MTD?
I am working on an embedded Linux system (kernel-5.24) and the development host is running WSL2 in Windows.
There is a NAND FLASH of 128MB in the embedded system (PEB is 128KiB, page size is 4096 ...
- 387
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1
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238
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"structure needs cleaning", hardware failure?
The drive that my /home folder lives on is showing signs of failing,
and I'm trying to migrate to a new drive.
I purchased a 4TB SSD, formatted it with ext4, mounted it as an external drive with a ...
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1
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45
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Any operations with file system takes forever
I'm using Ubuntu 22.04 LTS. Unexpectedly for me all operations with the file system stopped working. I tried ls /, df and nautilus - all of this command takes forever to execute. What happened to my ...
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0
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30
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EOVERFLOW when opening any file for writing
I'm writing a custom container engine. When I attempt to open any file for writing somewhere in the container (as long as that place is writeable, permissions-wise), I get an EOVERFLOW error (Value ...
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3
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91
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In Linux how to find if a file was read and at what time
Is there a tool or command where we can see if a file was read and at what time? I would only find for last modified.
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23
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How do I get the number of hardlinks of a folder?
I am on Mac. However, I use gstat (GNU stat) so my understanding is that behavior should match linux.
I cd to a folder. Then I use gstat --format=%h .. The output is 65.
Next, I use gfind . -maxdepth ...
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5
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Why can't hard links reference files on other filesystems?
I'm aware that this article exists:
Why are hard links only valid within the same filesystem?
But it unfortunately didn't click with me.
https://www.kernel.org/doc/html/latest/filesystems/ext4/...
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1
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73
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"Bad Jump in FAT partition" and "Bad number of sectors per cluster" right before ext4 offset
TL;DR partition table (?) potentially messed up by windows disk management on drive containing both NTFS data partition and EXT4 filesystem. Fairly certain zero or almost zero data was lost. testdisk ...
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49
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Question on tuning file system cache in Linux UBIFS on MTD
I am working on an embedded Linux system, where kernel is 5.10.24, and UBIFS on MTD is used.
The testing team had a test, which writes a disk file (open, write, close in order), then powers system off....
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2
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74
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Is there a "reverse COW" filesystem or LVM feature for Linux?
Is there any sort of filesystem or volume manager on Linux that supports COW snapshots, but instead of writing out new blocks for a new snapshot, it copies the old, unchanged blocks and does an in-...
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Issue with open syscall in /tmp folder with uid 0 [duplicate]
I have conducted a small test which raised an issue i could not figure out.
Create file in /tmp named what as shell user (uid 1000), then make it 0666 (rw-rw-rw-)
Try to call open with uid 0 (root) ...
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1
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30
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Is there a standard way of making a copy of file/folder permissions to apply/compare later?
I'm copying a bunch of files to a filesystem that doesn't support permissions. however, I will need to copy them to another filesystem which does support permissions a few years from now. at that ...
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2
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69
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Are there any filesystems with builtin data repairing via checksums?
I've read that ZFS/BtrFS have a checksum check, but they don't use it for data recovery, only for recovering data from a full local copy or a mirror copy.
On the other hand, RAR archives support data ...
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1
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Unix-esque partial-file-locking mechanism
Linux and AFAIK most unixes expose the flock syscall for mandatory file-locking. My experience is admittedly limited with this, however am informed that it is kernel-enforced on the entire resource. ...
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Splitting disk writes between two filesystems based on file extension
Background
I am running a proprietary video & audio management application. It reads & writes large multimedia files but also uses a home-grown "database" for metadata. The database ...
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2
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666
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Why does this use of `cp -a` not preserve creation time?
I copy some directories with -a in order to preserve=all which I understood would include creation times:
cp -a ./* /mnt/destination/
When inspecting the resulting directories in the destination they ...
- 511
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26
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How to reclaim SSD space during formating
I've got a "1000GB SSD"
after creating partition (aligned to 2048) I'm down to
sdd 8:48 0 931.5G 0 disk
└─sdd1 8:49 0 931.5G 0 part
which is fine, because 1GB means 1000bytes ...
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211
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How to free memory in root file system
I have a lap top that has had Arch Linux installed for approximately two years. Yesterday, when conducting a daily update via the command sudo pacman -Syu I recieved the warning the volume Filesystem ...
- 155
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49
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Unmount root from /boot partition? trying to fstransform /dev/mapper/VolGroup-lv_root
I am trying to transform /dev/mapper/VolGroup-lv_root from xfs to ext4 using fstransform on my CentOS 7 VM. This is needed for a migration from another Centos 7 VM. The issue I am facing is the root ...
