Support for 16K EXT3?

Using TestDisk to repair the filesystem
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ChesterTField
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Support for 16K EXT3?

#1 Post by ChesterTField » 04 Oct 2013, 17:33

I'm wondering if testdisk has support for EXT3 with 16K blocks... Unfortunately NetGear used 16K EXT3 in their SPARC-based ReadyNAS boxes and my motherboard (on the NAS) has died.

I was able to recover the system/configuration partition (formatted as 4K EXT3) but I'm unable to mount the larger EXT3 filesystem. I noticed on git that there was a recent commit for 64K block sizes, would this also include 16K blocks?

Thanks!

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cgrenier
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Re: Support for 16K EXT3?

#2 Post by cgrenier » 05 Oct 2013, 13:38

I have uploaded a new 7.0-WIP version that allow this blocksize. Can you try it ?

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Re: Support for 16K EXT3?

#3 Post by ChesterTField » 06 Oct 2013, 03:53

Thanks Christophe,

I ran testdisk again but the log file still looks like it's seeing (or assuming) 4K blocks:

recover_EXT2: s_block_group_nr=0/8843, s_mnt_count=13/4294967295, s_blocks_per_group=32768, s_inodes_per_group=16384
recover_EXT2: s_blocksize=4096
recover_EXT2: s_blocks_count 289775616
recover_EXT2: part_size 2318204928
ext3 17640 0 1 289793255 1 4 2318204928 [c]
ext3 blocksize=4096 Large file Sparse superblock Recover, 1186 GB / 1105 GiB

Here's the MD5sum of the version I used:

07b794899f8632416f070c19082f07cf testdisk-7.0-WIP.tar.bz2

I've tried photorec and it is able to restore some data, lots of the JPEGs are corrupt though, so I'm still hoping the filesystem can be mounted again... maybe wishful thinking...

I noticed when I do a Deep Search I get a lot (screens full) of ext3 possible ext3 partitions but they all are empty:

Disk /dev/md2 - 1192 GB / 1110 GiB - CHS 291096576 2 4
Analyse cylinder 4986627/291096575: 01%


ext3 14006 0 1 289789621 1 4 2318204928 [c]
ext3 14038 0 1 289789653 1 4 2318204928 [c]
ext3 14045 0 1 289789660 1 4 2318204928 [c]
ext3 14072 0 1 289789687 1 4 2318204928 [c]
ext3 14141 0 1 289789756 1 4 2318204928 [c]
ext3 14179 0 1 289789794 1 4 2318204928 [c]
ext3 14220 0 1 289789835 1 4 2318204928 [c]
ext3 14229 0 1 289789844 1 4 2318204928 [c]
ext3 14241 0 1 289789856 1 4 2318204928 [c]
ext3 14253 0 1 289789868 1 4 2318204928 [c]
ext3 14275 0 1 289789890 1 4 2318204928 [c]
ext3 14495 0 1 289790110 1 4 2318204928 [c]
ext3 14688 0 1 289790303 1 4 2318204928 [c]
ext3 14717 0 1 289790332 1 4 2318204928 [c]
ext3 14729 0 1 289790344 1 4 2318204928 [c]
ext3 14778 0 1 289790393 1 4 2318204928 [c]
ext3 14784 0 1 289790399 1 4 2318204928 [c]
ext3 14796 0 1 289790411 1 4 2318204928 [c]
ext3 14804 0 1 289790419 1 4 2318204928 [c]
... etc, etc ...

/dev/md2 is recognized as an LVM Partition but unfortunately I can't seem to get the logical volume to do any better (almost exact same result with partition set to None -- which I believe it should be?)

This was the old fstab, which makes me think there was no partition table previously:

/dev/c/c /c ext3 defaults,acl,user_xattr,usrquota,grpquota,noatime

So the more I think about this I'd wondering if I should be looking at e2fsck with blocksize 16*1024 (and the -n option of course).

root@solar:/usb/solar# sigfind -b 16384 ef53 /dev/c/c
Block size: 16384 Offset: 0 Signature: EF53
Block: 22546 (-)
Block: 230372 (+207826)
... still running ...

I'll see what I can find out when it's finished scanning. If the signatures are stored on disk as little-endian and the CPU is (was) SPARC should I be looking for ef53 or 53ef?

Thanks!

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Re: Support for 16K EXT3?

#4 Post by cgrenier » 14 Oct 2013, 16:08

TestDisk reports the blocksize it reads in the superblock. Maybe 16K was used but 4K written in the superblock. To test it, run PhotoRec, enable the Expert mode in Options, select the partition and start a recovery. Use 16k for the blocksize. Use the default options otherwise. Do you get more jpg this way ?

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