Query: ext4 meta data size calculation error?

[procount]

noobs/recovery/multiimagewritethread.cpp

Line 99 in 54ac40f

totaluncompressedsize += /*0.035*/ 0.01 * totalnominalsize; /* overhead for file system meta data */

I think the above line is supposed to add 1% overhead in size to account for the ext4 metadata. But it seems to be adding 1% of the accumulated total of all the partitions so far encountered. Shouldn't it be 1% of the nominal size of THIS partition only?

[lurch]

Oooh, well spotted. Given that the code is inside a foreach loop, I suspect that it was supposed to be:

    totaluncompressedsize += /*0.035*/ 0.01 * partition->partitionSizeNominal(); /* overhead for file system meta data */

Looking through the git history, it seems that bug has been there since 2013 😉
And maybe if the bug does get fixed, the "1% overhead" value would need tweaking? 🤷‍♂️

On the plus side, I guess over-estimating the needed space is much better than under-estimating the needed space 😆

[procount]

Yeah, that's what I changed mine to.
I spotted it whilst trying to make the progress bar more accurate.
Making good progress, but currently I have to set this tweak parameter to 5% for Raspbian_Full. Not tried any others in anger yet.