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Re: ext3_free_blocks_sb when removing a more than 1GB file

On Fri, Mar 4, 2011 at 2:17 PM, Andreas Dilger <adilger dilger ca> wrote:
On 2011-03-04, at 11:07 AM, Stephane Cerveau wrote:
> I have several keys from the same brand, model and I have the same issue.
> When I said, a different key, it was a different brand.

I would typically blame the USB key.  Some cheap vendors use unreliable chips, and sometimes even mis-label e.g. 1GB flash as 2GB.

> At the end, it seems that ext2 is working fine!

Except I don't think ext2 is doing this bitmap validation at runtime, like ext3/4 is doing.

I'm not sure whether "badblocks" is verifying that the storage is behaving correctly (i.e. correct block addressing), or only whether it is able to write/read a particular sector on disk.

You could use a more advanced block device verification tool, like llverdev from Lustre, which writes a unique test pattern to every block, and then reads it back afterward.
Quick test, in the meantime:

badblocks -n -t0xffff /dev/the_thumb_drive

-n is non-destructive.  -w is destructive of data.

then I'd try '-n -trandom -p5'
If you don't mind losing the data (I don't think you do), then use -w, rather than -n.

Stephen Samuel http://www.bcgreen.com  Software, like love,
778-861-7641                              grows when you give it away

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