Tagged Questions

A filesystem is a way to organize and store computer files with their data.

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1answer
246 views

Why isn't sda1 showing up in dev and how can I fix that?

I have an embedded Linux device and I was trying to copy some files to it. I plugged in a USB stick, the dmesg shows that it was recognized, but for some reason /dev/sda1 never showed up. I'm trying ...
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3answers
85 views

How to interact with the concrete file system?

Can a userspace program interact with the concrete file system(not VFS). What i have got is, that VFS allow linux to treat all file systems alike and gives a abstracted api to user space. I want to ...
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1answer
42 views

btrfs snapshots without subvolumes?

I'm starting to use btrfs. I want to be able to snapshot certain directories but do not want to create sub-volumes. Is this possible?
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3answers
74 views

“Other” permissions on files

To my understanding, the last three character of file permission printed by ls command is about other user's file permission. If the other user"s" have separate file permissions to this file, what ...
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2answers
92 views

live dd over a mounted read-only root partiton

I'm trying to conceive a firmware update mechanism for a Linux-based embedded system without an additional initrd/initramfs/whatever. From within the running system which has a read-only mounted root ...
1
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1answer
80 views

How to install a .bin file that gives the error that it needs more space in /tmp?

Here is the error: ~]$ ./jdev_suite_121200_linux64.bin 0%....................................................................................................100% Not enough disk space in dir ...
0
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1answer
81 views

Access Windows File System From Linux OS

My sister's computer has stopped working. I am not entirely sure what the problem is, but I think it is a Windows/software issue. She really just wants to retrieve the pictures off it. I am ...
1
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1answer
76 views

How can I determine the cause of CF card corruption?

I installed qnx in my CF card and made it bootable and it was working well. However, yesterday it stopped working while my system was running. Checking the filesystem revealed that it was corrupted. ...
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3answers
312 views

What is the difference between path and directory?

I don't understand the difference between path and directory. Could someone explain to me with examples?
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1answer
29 views

backup inode table on ext2/3/4

is it possible, to backup on regular basis inode table (including all inode information) on ext2/3/4? If yes, how to do it, or which program to use?
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4answers
542 views

Corruption-proof SD card filesystem for embedded Linux?

Recently we had a rather unpleasant situation with our customer - Raspberry Pi based "kiosk" used to display remote sensing data (nothing more fancy than a kiosk mode browser displaying a ...
5
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1answer
264 views

Kernel panic when passing noatime in bootargs

I have an embedded system using jffs2 and want to pass rootflags=noatime in the kernel bootargs parameter. This results in a kernel panic: jffs2: Error: unrecognized mount option 'noatime' or ...
2
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1answer
47 views

How can I partition and format my disk to an accuracy of “LBA” by commands?

How can I partition /dev/sdb into /dev/sdb1 and /dev/sdb2, and then format /dev/sdb1 to exFAT ( or FAT32 ) from LBA=1 to 2097152 by commands? ( LBA=0 is reserved for MBR )
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2answers
67 views

Shrink btrfs from /dev/sda to /dev/sda1

suppose I have 2 btrfs filesystems: one mounted on /mnt/big spanning across /dev/sda /dev/sdb /dev/sdc /dev/sdd the other mounted on /mnt/small on a single drive: /dev/sde How would I shrink the ...
3
votes
1answer
75 views

How to evaluate if it's worth using deduplication?

I have a partition where I am considering to use deduplication. For the profile of it's data I think it will be a good choice. Still, before doing it, I would like to evaluate the impact in a more ...
1
vote
3answers
171 views

File missing after fsck

Recently, my HDD crashed and I had to run a fsck command. Many files were moved to the lost+found folder and I've retrieved the important ones using find and grep, but I can't find my SQL databases. ...
3
votes
1answer
360 views

Booting using initramfs instead of uramdisk

I am working on Zynq Microzed board. It is booting perfectly with uramdisk.image.gz but I trying to boot it with initramfs.cpio. In this regard I have made following changes in header files of ...
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4answers
116 views

Hiding data in filesystems

I want to hide some files such that not even 'ls -a' can find it. I'm not talking about adding '.' in front of the filename. I was thinking if I could create separate system calls for accessing those ...
3
votes
2answers
881 views

Make part of read-only filesystem writable

I have a filesystem on flash using jffs2. I would like to mount this filesystem read-only, except for a single folder that I would like to be writable. Is this possible without resorting to something ...
3
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1answer
96 views

Does du or df perform caching?

I was wondering if there is any caching done with these utilities. I assume not, but not positive. Are there any typical similar utilities that do use caching to speed up results on subsequent runs? ...
3
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1answer
61 views

filesystem that works under qemu and I can mount on my host

I'm using qemu for different kind of tasks, I would like to pick a filesystem that is both qemu-compatible and easy to mount under my host. I already discarded both qcow and qcow2 because apparently ...
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5answers
531 views

Is there a more succinct alternative to piping to wc for counting files in a directory

If I do ls -1 target_dir | wc -l, I get a count of files in a directory. I find this a bit cumbersome. Is there a more elegant or succinct way?
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4answers
530 views

How to check physical device contents

I got a server with 2 hard drives. I would like to know what is on 2nd drive. How would I list all contents on physical device ? lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT xvda 202:0 0 ...
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3answers
1k views

EXT3: If block size is 4K, why does ls -l show file sizes below that?

If you run ls -l on a file that contains one letter, it will list as 2B in size. If your file system is in 4k blocks, I thought it rounded files up to the block size? Is it because ls -l actually ...
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0answers
60 views

Unable to make file system writtable no matter what

I have a flash card SanDisk of a camera which I plug in into my computer: $ lsblk mmcblk0 179:0 0 3.7G 1 disk └─mmcblk0p1 179:1 0 3.7G 1 part $ mount /dev/mmcblk0p1 on ...
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1answer
138 views

How to make an unallocated space “exist”?

I have Ubuntu and Windows installed together. I'm going to install Arch also along with them. For now, I what them to live there all together in my computer. I have the following: I'd like to ...
2
votes
2answers
808 views

Unable to remove the files from an usb drive (neither by dd /dev/zero nor by rm -r)

I have a flash usb drive and up till now it has worked well. Recently I recorded iso to it using dd. Now I want to delete it. $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT ....... sdb ...
6
votes
2answers
885 views

“Converting” a filesystem from ext3 to ext4

I've read on some Q&A on this website that one can "convert" an ext3 filesystem to ext4 without formatting, by issuing tune2fs -O extents,uninit_bg,dir_index /dev/dev-name And then running ...
4
votes
1answer
705 views

How to reset password on an encrypted fs?

I've got a laptop which I haven't used since the last summer vacation: I did put Debian 7 on it and used Debian's feature to fully encrypt the disk, besides a tiny bootloader (or a tiny partition) I ...
1
vote
1answer
138 views

Files that do not exist, prevent me from deleting them, corrupted filesystem

Well... It's about on an OS X system (hfs+), but that's unix after all to. :p system has become unbootable, due to a filesystem error... fsck.hfsplus fails because .... ... ** Checking ...
1
vote
1answer
104 views

Starting my own application at the startup

I am working on zc702 board having ARM Cortex A 9 processor. I have a binary that I got after cross-compilation for ARM (LED blinking). Now I want that this file should execute as soon as the the ...
3
votes
0answers
90 views

Optimal rootflags for rootfs for ext4 file system running on USB thumdrive [closed]

I have made myself a bootable USB Debian 7 thumbdrive, using debootstrap. It boots nicely - but occasionally freezes for a bit. I can see the load average is much higher than the running tasks should ...
1
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2answers
99 views

How can I find out about “rootfs”

Running Debian 7; when I execute a cat /etc/mtab I can see all sorts of useful information about the filesystems that are mounted, such as the filesystem and options used to mount then; however ...
2
votes
1answer
357 views

Why do deleted files continually reappear?

I've been having a strange issue recently, where I would delete files from a location (i.e. Desktop), and then empty the Trash. However, a day or so later (I'm not sure exactly what triggers it), the ...
0
votes
1answer
25 views

What is the encryption function in Encfs?

I'm a newbie at Encfs. After I read a paper about Encfs, I figured out there is a Encryption layer in Encfs. So I tried to find exact encryption function. but I couldn't find that because there are ...
1
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0answers
27 views

How is default readahead value determined

I have two different devices running XFS and the default readahead value set differs between the two disks. Why is that ? How is the default size computed ? Is it device dependent ? I might also add ...
4
votes
1answer
166 views

Backup of a ubi file system with dd?

A have a root file system (file system - image containinf folder structure and content) on a flash drive. The flash drive uses UBI as the underlying file system file system - the way the data blocks ...
5
votes
3answers
192 views

What filesystem metadata operations are actually journaled in ext4 & xfs?

I can't find a simple, straight answer about which filesystem metadata operations are actually persisted to the ext4 & xfs filesystem journals. Note that I am not inquiring about what POSIX ...
3
votes
2answers
372 views

Moving unallocated space from Extended partition to create a Primary partition

This is my partition structure : I want to create another primary partition from that unallocated space. If I shrink sda2 to a size less than what I needed for to create another primary partition, ...
3
votes
3answers
253 views

Speed up copying 1000000 small files

I have 1000000 4-20 kb files in a dir. I need to copy that dir. But it seems I have to do a seek for each files so this takes quite a while. Is there a way in which I can speed this up? I am ...
1
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0answers
154 views

Replacing default initramfs with my own

I followed this article to develop my own sample intramfs.cpio Now I have to put this in my kernel and compile. The procedure that I follw for petlinux is that I first run petalinux-config (and ...
1
vote
1answer
36 views

The libblkid library: any way to use it with blocks in the core memory?

I know how to use the libblkid library to analyze existing block devices. I'd like to use it to analyze a memory extent before I write it to the block device. Something like that: char block[4096]; ...
2
votes
1answer
59 views

The libblkid library: what is the 'blkid_superblocks_get_name' function for?

I'm trying to use the libblkid library to analyze various filesystems on a block device from a C/C++ program, and it works well. However I'm confused with the blkid_superblocks_get_name function from ...
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votes
8answers
846 views

Do I require a file system when I do not want to store any data

I asked a question here Is it mandatory to have a file system One of the comments is : how a system without file system would work on linux as even a printer or ethernet card is considered as ...
1
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1answer
185 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 ...
1
vote
1answer
141 views

File has bytes - appears to be empty

I'm having the following problem: Some text files (also some binary files) on my system are listed with the correct file size but when I open them, they appear empty. >ls -la -rw-rw-r-- 1 user ...
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0answers
325 views

No filesystem could mount root, tried: jffs2

CPU: ARM Cortex A-9 This is the kernel command line that I appears in configuration menu root=mtd:jffs2 rw rootfstype=jffs2 console=ttyps0,115200 I have put three files in flash: BOOT.BIN in mtd0 ...
2
votes
4answers
618 views

Why is writing SLOW on raw device, and FAST on filesystem (USB key)?

I have a USB key (PQI U822V-Speedy 32G) that I am trying to benchmark quick'n'dirty on Linux. I'm testing write bandwith. dd on raw partition I created a partition starting at sector 2048, then did ...
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3answers
43 views

Verify semantic integrity of filesystem

I just started up my linux box to find that one of my filesystem's had errors: I had to login as root to run fsck and hit y repeatedly. There were a lot of errors. So many that I used silly putty and ...
13
votes
2answers
482 views

Is that possible to integrate zip and tar.gz files as directory into the file system

I wonder if there is a way to integrate (it's a bit different from mounting, I think) compressed files as directories into the file system? E.g., one could download a compressed-file.tar.gz to his ...