Questions tagged [vfs]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
5
votes
2answers
111 views

Is file creation totally ordered?

On Linux, the openat syscall can be used to create files and to test for their existence. Speaking in terms of the C/C++ memory model, creating a file and verifying its existence creates a ...
0
votes
1answer
105 views

Where is the file creation time (birth) stored in linux?

Using debugfs -R 'stat <inode_nr> ' /dev/sda1 returns a result where there is a field crtime which i believe represents the creation date of a file pointed to by inode numbered inode_nr. I use ...
-2
votes
1answer
63 views

Does the virtual filesystem work on top of character devices and network subsystems?

Does the virtual filesystem work on top of character devices and network subsystems, or just on top of filesystems and block devices? Could you also explain a bit about in what sense "the VFS is ...
1
vote
1answer
69 views

using VFS to do dynamic mounting

I have what may sound like a strange situation. I have a mount point for a directory containing a variety of log files. From time to time it is necessary to unmount this directory and remount it in ...
1
vote
0answers
415 views

NFS Server - VFS: max file limit reached

I've been trying to determine why/how my CentOS 7.3 NFS server hung, and I'm hoping to gain some insight or direction with this post. The machine's purpose is to serve NFS storage to clients. I use ...
0
votes
0answers
1k views

How to take read all the partitions from eMMC dump

We have Beaglebone Black based custom board with 4GB eMMC and 256MB RAM. eMMC is partitioned as follows # parted --list Model: MMC MMC04G (sd/mmc) Disk /dev/mmcblk0: 3842MB Sector size (logical/...
3
votes
0answers
312 views

How does Linux resolve pathnames with the help of the dentry cache?

While dealing with the Virtual Filesystem of Linux I have come across a little problem of understanding how pathnames are resolved if they are already cached as dentries in the dentry cache. I know ...
2
votes
2answers
73 views

Where does the file size comes from, i.e. , how does ls and cp know the file size?

Recently I had a file that reported a file size of 33P bytes in my 500GB SSD, more details here. That was through ls and cp would report that there was no enough space. In my short knowledge and ...
2
votes
2answers
406 views

How do I run the usermode linux kernel?

I followed the steps here and compiled the kernel successfully in usermode: https://btrfs.wiki.kernel.org/index.php/Debugging_Btrfs_with_GDB But when I start ./linux in various ways it always gives ...
0
votes
1answer
170 views

Does the content of the file ever get cached by VFS? [closed]

If you read a text file for example, does its content ever get cached or is it always the address of the disk that gets cached?
0
votes
1answer
433 views

How to interpret VFS usage chart

I'm monitoring an old laptop running as LAMP server. I have trouble understanding this VFS usage chart (sorry can't include images yet) from monitorix (the monitoring tool I'm using). I don't ...
4
votes
2answers
284 views

confused about dd write speed and VFS page cache

After reading some articles on the Linux VFS page cache and the tunable parameters like dirty_ratio i was under the impression that page cache would operate as both read and write caching layer. But ...
1
vote
0answers
53 views

How much control do concrete file systems have over the VFS inode cache and the buffer cache?

I want to make sure I'm understanding how VFS inodes and file system inodes working together. A file system's inodes are stored on the block device and that is where they live. When an operation is ...
2
votes
0answers
32 views

Which subsystem caches file reads?

I am trying to understand how exactly file reads are served from Page Cache. This will be useful when I will be implementing my own filesystem in the kernel. Is file content cached by VFS or ...
2
votes
0answers
191 views

New inode when mounting new file system

Does kernel really create any new inode when some file system gets mounted on some directory of root file system? I don't expect it to create as there is no new files are being created. Is there some ...
0
votes
2answers
182 views

is VFS a module?

While studying VFS, this question popped into my head. Is it okay to think of VFS as a module? The reason why I thought like that is because VFS has the characteristic of simplifying actual file ...
1
vote
1answer
359 views

Why are the first inode of the `/` mounted partition and inode of `/` different?

[~]$ stat -c %i / 2 As you can see in above, the inode for / is 2. But the First inode of /dev/sda2 is 11. [~]$ df -h Filesystem Size Used Avail Use% Mounted on /dev/sda2 ...
0
votes
1answer
969 views

What is kernel memory and user memory? (question about the term kernel page and the page cache)

Today, I have read through some documents about file system (http://tekrants.me/2014/07/14/linux-file-system-write/). And the term kernel page is mentioned several times in this article. I am now ...
1
vote
1answer
85 views

Reading ELF file after dropping caches

I have an eMMC backed Linux 3.10 development device (Android) and I am trying to better understand when Linux is actually reading from the eMMC as opposed to the page cache. Specifically, I am ...
1
vote
1answer
943 views

Docker in Crouton - VFS consuming astronomical amounts of space

I'm attempting to help out a roommate who has installed Kubuntu on his Chromebook using Crouton (it's basically just a fancy chroot run within ChromeOS). I helped him get the Docker daemon running, ...
1
vote
1answer
95 views

How do I merge (without copying) two directories? [duplicate]

I have: $ find 1 2 -printf '%i %p\n' 40011805 1 40011450 1/t 40011923 1/a 40014006 1/a/e 40011217 1/a/q 40011806 2 40011458 2/y 40011924 2/a 40013989 2/a/e 40013945 2/a/w I want: <inode> <...
1
vote
1answer
191 views

Is there a way to achieve context-dependent path names (CDPN) on NFS?

In my GFS clusters I use the CDPN feature to have separate chrooted /dev/log directories on separate cluster nodes: /home/ftpuser/foo: lrwxrwxrwx 1 root root 18 Sep 26 2010 dev -> .sys/@hostname/...
5
votes
1answer
223 views

How do I temporarily extract a flash drive or HDD in Linux?

Suppose I mounted a disk in this way: mount /dev/sdb /mnt/tmp I have some files opened on this filesystem and don't want to unmount it. However I want to temporarily extract the device, then ...
3
votes
0answers
117 views

Tool for dumping Linux VFS superblock

From the dumpe2fs man page: dumpe2fs prints the super block and blocks group information for the filesystem present on device. So dumpe2fs will dump the filesystem superblock. Is there any such ...
0
votes
1answer
3k views

Centos VFS cannot open root device

Yesterday I did a kernel update on a virtual machine. When I restarted the machine unfortunately I got the error Kernel panic - not syncing VFS After some searching I found out I should go to GRUB ...
1
vote
0answers
379 views

Limiting the total size of samba's vfs_recycle by pruning oldest deleted files first

Running SerNet Samba 4.0.9 on CentOS 6.4 serving as an AD DC and fileshare for XP clients. Added recycler per the example here. My concern is that the recycle dir will eventually grow large. ...
8
votes
2answers
2k views

Linux cache evictions

Looking at how the VFS cache on my Linux machine behaves, I can see that even when effectively idle (crond and most other daemons stopped, interfaces down) the amount of free memory gradually ...