A partition is unusable after cfdisk maximize

completed_tzinfe · 10-29-2011, 10:12 AM

Hello,

A while ago I used cfdisk to partition my hard drive. During the partitioning, I told cfdisk to maximize the partition with my data (ext3), because it had some unallocated space before and after it.
As a result result, I cannot use the partition now.
I tried turning that option later on, however I still couldn't use it.
mount -t ext3 /dev/sda5 /media/sda5 says that the partition type is unknown.
gparted says that the partition type is unknown.
ext2explore (on windows) doesn't see this partition at all.
acronis disk director (on windows also) says that the partition is not formatted.

Thanks in advance

TobiSGD · 10-29-2011, 10:30 AM

You resized only the partition, but not the file system on it. Have a look at the resize2fs program, its purpose is to resize ext2/3/4 filesystems.

completed_tzinfe · 10-29-2011, 06:07 PM

Quote:

Originally Posted by TobiSGD

You resized only the partition, but not the file system on it. Have a look at the resize2fs program, its purpose is to resize ext2/3/4 filesystems.

Thanks for the fast reply, TobiSGD, but could you please be more specific about the way I need to use this program?

Here's what I get when I try to do it (as root, of course):
resize2fs /dev/sda5

resize2fs: Bad magic number in super-block while trying to open /dev/sda5
Couldn't find valid filesystem superblock.

TobiSGD · 10-29-2011, 07:14 PM

I never used that program, so I can only recommend to read the manpage for it with

Code:

man resize2fs

syg00 · 10-29-2011, 08:51 PM

Hmmm - did you happen to take note of the warning(s) re using that (maximize) command ?.
I guess not.

Anything referencing the filesystem (like mount and resize2fs) I would think would expect it to be at the "start" of the partition. If you've expanded the partition in "front" of the filesystem, obviously this would no longer be the case.
resize2fs works fine when the partition is larger at the "end".

The following from the manpage has always been my primary concern when screwing around with partitions/filesystems:

Quote:

When recreating the partition, make sure you create it with the same starting disk cylinder as before! Otherwise, the resize operation will certainly not work, and you may lose your entire filesystem.

I would think you could loop mount the filesystem using an offset just to prove it is o.k. Could get fiddly, but would allow you to back everything up. Might then be easier just to mkfs and copy it all back - or you could try playing around to get the partition to again match the filesystem.

business_kid · 10-30-2011, 03:54 PM

I would delete the partition, try with testdisk, and carefully choose the smaller partition to restore if testdisk spots it. You may end up with numbers out of sequence, but a little hacking of fstab fixes thatTestdisk has a static binary download, which has all the libs compiled in.

Then stop messing, & ignore messages as long as it works.