Bug#793326: linux: raid0 data corruption when using trim

[Matt Taggart <taggart@debian.org>]

Package: linux
Version: 4.1.2-1~exp1

The company Algolia discovered a problem when TRIM was enabled on their 
SSDs and documented things on their blog as they tracked it down

https://blog.algolia.com/when-solid-state-drives-are-not-that-solid/

At first it was thought to be a problem with enabling TRIM on the Samsung 
SSDs, but with the help of Samsung the problem was eventually found to be 
due to a "misunderstanding between raid driver and scsi/ata driver" and a 
patch was posted

  http://www.spinics.net/lists/raid/msg49440.html

to which Martin K. Petersen followed up with a different version

  http://www.spinics.net/lists/raid/msg49447.html

and that patch was tested and submitted

  http://www.spinics.net/lists/raid/msg49468.html

The bug affected raid0 and raid10 (but apparently not raid1) when TRIM was 
enabled. Apparently it's been around a while, it probably exists older 
debian releases but I have not checked.

Also: as the blog June 16th update states, this bug was NOT related to 
queued TRIM as they didn't have that enabled, so probably unrelated to 
#790520.

Thanks,

-- 
Matt Taggart
taggart@debian.org