On 09/05/2012 03:59 AM, Shentino wrote:
> I am not sure that doing "sed</dev/sdX>/dev/sdX ..." is the right thing to
> do, because it rewrites the full disk. This means that:
> - it takes a lot of time
> - you don't have any control about which part of the disk you change: what
> happens if sed write a block which is update in parallel by BTRFS ?
Which is one reason I used a sha1 hash of a random read as the search key :P
This doesn't change. The race would be the following:
1- kernel read a sector from the disk
2- sed read a sector from the disk
3- sed write a sector to the disk (the same data or an update one
doesn't matter)
4- kernel write an update sector to the disk
If 3 and 4 are different data the results are unpredictable. Yes it is a
very unlikely case, but it could happens.
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