mounting mmcblk0p1 failed with Invalid argument

Question

When I am running linux from sd card and try to mount sd card -no problem, works fine. But when I am running linux from flash memory I am unable to mount my SD card:

# mount /dev/mmcblk0p1 /mnt/ 
mount: mounting /dev/mmcblk0p1 on /mnt/ failed: Invalid argument

What could be the basic reason for this error ?

Additional Info

root@Xilinx-ZC702-14_7:/# mount -t /dev/mmcblk0p1 /mnt
mount: can't find /mnt in /etc/fstab 

root@Xilinx-ZC702-14_7:/var/volatile/log# ls
wtmp

root@Xilinx-ZC702-14_7:/var/volatile/log# dmesg
dmesg: klogctl: Function not implemented

Answer 1

As commented by goldilocks, mount -t expects the filesystem type to come after -t, so it won't work. Otherwise it sounds like you just need to specify the filesystem type. If you don't know the filesystem type, then there are a list of methods to find out in this answer. If the file command is available, this is probably the best method. As root you would do:

file -s /dev/mmcblk0p1

Note also that if the filesystem type is not in listed in /proc/filesystems, then the driver is not compiled into the kernel and so must be available as an external module. Once you have the correct type, you can try:

mount -t correct_type /dev/mmcblk0p1 /mnt

As a final thought, also make sure the /mnt directory exists! If not create it with mkdir /mnt.

Answer 2

Basic reasons: (updated)

1) Your system does not (properly?) initialize or does not recognize the SD when booting from flash. Is there the /dev/mmcblk0 device after you boot from flash? What does fdisk -l /dev/mmcblk0 say?

2) There is no file system on /dev/mmcblk0p1, you need to create a file system first (mkfs ...). Check with file -s /dev/mmcblk0p1

3) The file system on /dev/mmcblk0p1 is corrupted, you need to check / repair it, try fsck /dev/mmcblk0p1, or create a new one

4) Your kernel (when booting from flash) does not have the needed file system driver, check cat /proc/filesystems and ls "/lib/modules/$(uname -r)/kernel/fs/" and see if that list contains the needed file system type. Typically, older kernels don't support ext4, while your OS might already have tools to create an ext4 file system.

5) Hardware defect - could be the SD card, the controller, wiring ... but if it works when booting from the SD card then this is most probably not the case.

Answer 3

First check the file systems supported in the kernel.

[kevin@hexcore ~]
$ cat /proc/filesystems 
....
    ext3
    ext2
    ext4
....

I assume that you are trying to mount the same SD card from which you are running the Linux. If so, I assume, quite reasonably, that it has native file system support in Linux. To make sure you have loaded the SD card driver, you can try,

$ sudo modprobe sdhci
$ dmesg | tail -n 10
sdhci: Secure Digital Host Controller Interface driver

Now, try read access to partitions:

$ sudo dd if=/dev/mmcblk of=/dev/null bs=4k count=0  # note: count = 0

Alternatively:

$ sudo fdisk -l /dev/mmcblk

fdisk will tell you the partition types as well.

This assures you that the SD card driver can access the block device. Now you can run parted to print the file systems:

$ sudo parted /dev/mmcblk
(parted) p
Number  Start   End     Size    Type     File system     Flags
 1      1049kB  8000MB  7999MB  primary  linux-swap(v1)
 2      8000MB  500GB   492GB   primary  ext4

Once you know the FS, mount it with

$ sudo mount -t <FS> /dev/mmcblkpX </target/dir>

Answer 4

I seem to remember this is the error you get when the type of partition you're trying to mount isn't supported.

Answer 5

Maybe you need to use (parted command) due to partition size:

# /sbin/parted /dev/mmcblk0p1
(parted) mklabel gpt
this disk will be lost. Do you want to continue?
Yes/No? yes
....
(parted) quit

To make sure that the partition is properly created use /sbin/parted /dev/mmcblk0p1 print”

Then you have to format the created partition

/sbin/mkfs -t correct_type /dev/mmcblk0p1