A Linux bug you can now understand

Hi all students from INFO0940, I came accross a bug which may ring multiple bells for you (sorry, it’s in french) :

http://www.developpez.com/actu/85653/Linux-decouverte-d-un-bug-sur-le-systeme-de-fichiers-EXT4-qui-pourrait-causer-une-importante-perte-de-donnees/

The bug description should remember you some all ghost :
« La variable “sector” dans “raid0_make_request()” n’a pas été correctement modifiée par l’appel à “sector_div()” qui modifie son premier argument à la place. Le commit [précèdent] restaurait cette variable après l’appel pour une utilisation ultérieure. Malheureusement la restauration a été effectuée après que la variable “bio” a été avancée »

I know multiple people had problems with dividing sectors and using sector_div(). Fortunately, most of you used it correctly ! Maybe you should help them :p I wonder if the bug could happen with any file system as raid0_make_request seems to be related to MD and not to ext4 at all, maybe the article is poorely written and it was just seen with ext4 but is related to all md0 device?

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