sd card data broken after umount - linux

I wrote an SD host-controller Linux driver for a totally customized board, using IP TE4395.
With the driver I wrote,
I can mount an SD card, read and write.
when mounted, once I umount, the next mount will fail.
command mount -o remount /dev/mmcblk0p1 worked normally....
# ls /mnt/
aaa.txt lost+found
# mount -o remount /dev/mmcblk0p1
EXT4-fs (mmcblk0p1): re-mounted. Opts: block_validity,delalloc,barrier,user_xattr,acl
# echo adfaf >/mnt/bbb.txt
# ls /mnt/
aaa.txt bbb.txt lost+found
# cat /mnt/bbb.txt
adfaf
# sync
# ls /mnt/
aaa.txt bbb.txt lost+found
# umount /mnt/
# mount /dev/mmcblk0p1 /mnt
mount: mounting /dev/mmcblk0p1 on /mnt failed: Invalid argument

I know the reason.
the driver has a problem. I added some code for debug, that read register when driver write registers.
And the Data Port register is special, when access the register the buffer pointer inside the controller will be incremented automatically.
The debug code read before and after write to the register, so accessed the register 3 times, but expected just 1 time access(write).

Related

Fails to `mkdir /mnt/vzsnap0` for Container Backups with Permission Denied

This is all done as the root user.
The script for backups at /usr/share/perl5/PVE/VZDump/LXC.pm sets a default mount point
my $default_mount_point = "/mnt/vzsnap0";
But regardless of whether I use the GUI or the command line I get the following error:
ERROR: Backup of VM 103 failed - mkdir /mnt/vzsnap0:
Permission denied at /usr/share/perl5/PVE/VZDump/LXC.pm line 161.
And lines 160 - 161 in that script is:
my $rootdir = $default_mount_point;
mkpath $rootdir;
After the installation before I created any images or did any backups I setup two things.
(1) SSHFS mount for /mnt/backups
(2) Added all other drives as Linux LVM
What I did for the drive addition is as simple as:
pvcreate /dev/sdb1
pvcreate /dev/sdc1
pvcreate /dev/sdd1
pvcreate /dev/sde1
vgextend pve /dev/sdb1
vgextend pve /dev/sdc1
vgextend pve /dev/sdd1
vgextend pve /dev/sde1
lvextend pve/data /dev/sdb1
lvextend pve/data /dev/sdc1
lvextend pve/data /dev/sdd1
lvextend pve/data /dev/sde1
For the SSHFS instructions see my blog post on it: https://6ftdan.com/allyourdev/2018/02/04/proxmox-a-vm-server-for-your-home/
Here are filesystem directory permission related files and details.
cat /etc/fstab
# <file system> <mount point> <type> <options> <dump> <pass>
/dev/pve/root / ext4 errors=remount-ro 0 1
/dev/pve/swap none swap sw 0 0
proc /proc proc defaults 0 0
df -h
Filesystem Size Used Avail Use% Mounted on
udev 7.8G 0 7.8G 0% /dev
tmpfs 1.6G 9.0M 1.6G 1% /run
/dev/mapper/pve-root 37G 8.0G 27G 24% /
tmpfs 7.9G 43M 7.8G 1% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 7.9G 0 7.9G 0% /sys/fs/cgroup
/dev/fuse 30M 20K 30M 1% /etc/pve
sshfs#10.0.0.10:/mnt/raid/proxmox_backup 1.4T 725G 672G 52% /mnt/backups
tmpfs 1.6G 0 1.6G 0% /run/user/0
ls -dla /mnt
drwxr-xr-x 3 root root 0 Aug 12 20:10 /mnt
ls /mnt
backups
ls -dla /mnt/backups
drwxr-xr-x 1 1001 1002 80 Aug 12 20:40 /mnt/backups
The command that I desire to succeed is:
vzdump 103 --compress lzo --node ProxMox --storage backup --remove 0 --mode snapshot
For the record the container image is only 8GB in size.
Cloning containers does work and snapshots work.
Q & A
Q) How are you running the perl script?
A) Through the GUI you click on Backup now, then select your storage (I have backups and local and the both produce this error), then select the state of the container (Snapshot, Suspend, Stop each produce the same error), then compression type (none, LZO, and gzip each produce the same error). Once all that is set you click Backup and get the following output.
INFO: starting new backup job: vzdump 103 --node ProxMox --mode snapshot --compress lzo --storage backups --remove 0
INFO: Starting Backup of VM 103 (lxc)
INFO: Backup started at 2019-08-18 16:21:11
INFO: status = stopped
INFO: backup mode: stop
INFO: ionice priority: 7
INFO: CT Name: Passport
ERROR: Backup of VM 103 failed - mkdir /mnt/vzsnap0: Permission denied at /usr/share/perl5/PVE/VZDump/LXC.pm line 161.
INFO: Failed at 2019-08-18 16:21:11
INFO: Backup job finished with errors
TASK ERROR: job errors
From this you can see that the command is vzdump 103 --node ProxMox --mode snapshot --compress lzo --storage backups --remove 0 . I've also tried logging in with a SSH shell and running this command and get the same error.
Q) It could be that the directory's "immutable" attribute is set. Try lsattr / and see if /mnt has the lower-case "i" attribute set to it.
A) root#ProxMox:~# lsattr /
--------------e---- /tmp
--------------e---- /opt
--------------e---- /boot
lsattr: Inappropriate ioctl for device While reading flags on /sys
--------------e---- /lost+found
lsattr: Operation not supported While reading flags on /sbin
--------------e---- /media
--------------e---- /etc
--------------e---- /srv
--------------e---- /usr
lsattr: Operation not supported While reading flags on /libx32
lsattr: Operation not supported While reading flags on /bin
lsattr: Operation not supported While reading flags on /lib
lsattr: Inappropriate ioctl for device While reading flags on /proc
--------------e---- /root
--------------e---- /var
--------------e---- /home
lsattr: Inappropriate ioctl for device While reading flags on /dev
lsattr: Inappropriate ioctl for device While reading flags on /mnt
lsattr: Operation not supported While reading flags on /lib32
lsattr: Operation not supported While reading flags on /lib64
lsattr: Inappropriate ioctl for device While reading flags on /run
Q) Can you manually created /mnt/vzsnap0 without any issues?
A) root#ProxMox:~# mkdir /mnt/vzsnap0
mkdir: cannot create directory ‘/mnt/vzsnap0’: Permission denied
Q) Can you replicate it in a clean VM ?
A) I don't know. I don't have an extra system to try it on and I need the container's I have on it. Trying it within a VM in ProxMox… I'm not sure. I suppose I could try but I'd really rather not have to just yet. Maybe if all else fails.
Q) If you look at drwxr-xr-x 1 1001 1002 80 Aug 12 20:40 /mnt/backups, it looks like there are is a user with id 1001 which has access to the backups, so not even root will be able to write. You need to check why it is 1001 and which group is represented by 1002. Then you can add your root as well as the user under which the GUI runs to the group with id 1002.
A) I have no problem writing to the /mnt/backups directory. Just now did a cd /mnt/backups; mkdir test and that was successful.
From the message
mkdir /mnt/vzsnap0: Permission denied
it is obvious the problem is the permissions for /mnt directory.
It could be that the directory `s "immutable" attribute is set.
Try lsattr / and see if /mnt has the lower-case "i" attribute set to it.
As a reference:
The lower-case i in lsattr output indicates that the file or directory is set as immutable: even root must clear this attribute first before making any changes to it. With root access, you should be able to remove this with chattr -i /mnt, but there is probably a reason why this was done in the first place; you should find out what the reason was and whether or not it's still applicable before removing it. There may be security implications.
So, if this is the case, try:
chattr -i /mnt
to remove it.
References
lsattr output
According to inode flags—attributes manual page:
FS_IMMUTABLE_FL 'i':
The file is immutable: no changes are permitted to the file
contents or metadata (permissions, timestamps, ownership, link
count and so on). (This restriction applies even to the supe‐
ruser.) Only a privileged process (CAP_LINUX_IMMUTABLE) can
set or clear this attribute.
As long as the bounty is still up I'll give it to a legitimate answer that fixes the problem described here.
What I'm writing here for you all is a work around I've thought of which works. Note, it is very slow.
Since I am able to write to the /mnt/backups directory, which exists on another system on the network, I went ahead and changed the Perl script to point to /mnt/backups/vzsnap0 instead of /mnt/vzsnap0.
Bounty remains for anyone who can get the /mnt directory to work for the mount path to successfully mount vzsnap0 for the backup script..
1)
Perhaps your "/mnt/vzsnap0" is mounted as read only?
It may tell from your:
/dev/pve/root / ext4 errors=remount-ro 0 1
'errors=remount-ro' means in case of mistake remounting the partition like readonly. Perhaps this setting applies for your mounted filesystem as well.
Can you try remounting the drive as in the following link? https://askubuntu.com/questions/175739/how-do-i-remount-a-filesystem-as-read-write
And if that succeeds, manually create the directory afterwards?
2) If that didn't help:
https://www.linuxquestions.org/questions/linux-security-4/mkdir-throws-permission-denied-error-in-a-directoy-even-with-root-ownership-and-777-permission-4175424944/
There, someone remarked:
What is the filesystem for the partition that contains the directory.[?]
Double check the permissions of the directory, or whether it's a
symbolic link to another directory. If the directory is an NFS mount,
rootsquash can prevent writing by root.
Check for attributes (lsattr). Check for ACLs (getfacl). Check for
selinux restrictions. (ls -Z)
If the filesystem is corrupt, it might be initially mounted RW but
when you try to write to a bad area, change to RO.
Great, turns out this is a pretty long-standing issue with Ubuntu Make which is faced by many people.
I saw a workaround mentioned by an Ubuntu Developer in the above link.
Just follow the below steps:
sudo -s
unset SUDO_UID
unset SUDO_GID
Then run umake to install your application as normal.
you should now be able to install to any directory you want. Works flawlessly for me.
try ls laZ /mnt to review the security context, in case SE Linux is enabled. relabeling might be required then. errors=remount-ro should also be investigated (however, it is rather unlikely lsattr would fail, unless the /mnt inode itself is corrupted). Creating a new directory inode for these mount-points might be worth a try; if it works, one can swap them.
Just change /mnt/backups to /mnt/sshfs/backups
And the vzdump will work.

Programmatically obtaining USB file system format

I need to mount a USB drive to an embedded system, running Linux. The USB could be in FAT, NTFS or ExFAT format.
How can i handle this in code so that I pass proper type in mount command such as
mount -t vfat /dev/sda1 /mnt
So I have tried mount with:
mount -t vfat,ntfs /dev/sda1 /mnt
This command gives invalid argument, but it successfully mounts the USB if USB is in NTFS or VFAT format. However if i try to give
mount -t vfat,ntfs,exfat /dev/sda1 /mnt
The command fails.
Any pointers will be really helpful.
From the mount manual page:
If no -t option is given, or if the auto type is specified,
mount will try to guess the desired type. Mount uses the blkid
library for guessing the filesystem type...
Is libblkid available for your embedded system?
Try:
mount -t auto /dev/sda1 /mnt
or
mount /dev/sda1 /mnt
And as mentioned in the comments, make sure the kernel on your embedded system supports exfat.

Mount Squashfs as Root in initramfs Raspbian

I'm currently trying to make my raspbian boot from a squashFS image through initramfs.
The squashfs image is on file system /dev/mmcblk0p1, so I mount this prior to mounting the Image.
Unfortunately I'm stuck at mounting the SquashFS Image file.
I tried mounting through
mount -o loop
but I always get
mounting /dev/loop0 on /mnt/root failed: No such device
So I tried to mount it through loop manually. The problem is, that mounting the /dev/loop0 fails with the same Error as above.
This is my init so far:
#!/bin/busybox sh
# Mount the /proc and /sys filesystems.
mount -t proc none /proc
mount -t sysfs none /sys
#create loop devices
mknod /dev/loop0 b 7 0
mkdir /mnt/root
# Mount the boot partition
mount -o ro /dev/mmcblk0p1 /mnt/boot
sleep 5
# Mount the root FS with losetup
echo "Mounting with losetup"
losetup /dev/loop0 /mnt/boot/SYSTEM
mount /dev/loop0 /mnt/root -t squashfs
echo "Done"
#mount -o ro,loop -t squashfs /mnt/boot/SYSTEM /mnt/root
# Use Fallback mounting failed
if [ ! -e /mnt/root/home ]
then
echo "MOUNTING SDA1"
mount /dev/sda1 /mnt/root -t ext4
fi
# Clean up.
umount /proc
umount /sys
umount /mnt/boot
# Boot the real thing.
exec switch_root /mnt/root /sbin/init
Checking
losetup /dev/loop0
tells me, that the squashfs Image has been attached to loop0.
Does somebody know where to start?
I came across your question because I ran into the same thing today while building my own initramfs. I did some more digging and found this:
http://www.silas.net.br/doc.notes/unix/linux/busybox-troubleshooting.html
Then it dawned on me that I hadn't built squashfs into the kernel or loaded the module. After I did that, everything worked!
In case you haven't, make sure your kernel supports squashfs.

How to determine the type of file system on an SD Card

How to determine the type of file system on an SD Card (this card is not yet mounted. I need to determine the file system type so that i can mount the SDCard through a program according to the file system type)
Or from the terminal. For example "mount -t ext3 /dev/sdc1 /mnt"
You might do a file -s /dev/sdc1 and it could recognize the filesystem data.
And you might do mount -t auto /dev/sdc1 /mnt to have mount recognize it.

Ubuntu mount -t command

I use following command to mount "/dev/sdb1" to "/storage" directory:
mount -t ext3 /dev/sdb1 /storage
After run above command, I can use "df -h" can see it:
/dev/sdb1 147G 188M 140G 1% /storage
But after i restart the server, it disappear, and i have to run mount command again.
Is there a command that can keep the mount even if i restart the server?
Add the following line to your /etc/fstab file:
# device name mount point fs-type options dump-freq pass-num
/dev/sdb1 /storage ext3 defaults 0 0
You can run (as root):
echo "/dev/sdb1 /storage ext3 defaults 0 0" >> /etc/fstab
You need to add relevant information to /etc/fstab.

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