News for hackers. Stuff that matters.

A comment on I tested four NVMe SSDs from four vendors – half lose FLUSH'd data on power loss. Parent comment

Re:I tested four NVMe SSDs from four vendors – half lose FLU... by charleshn on Wednesday November 22, 2023 @01:35AM (#38375555)
It's likely because of delayed allocations (delalloc): https://issuetracker.google.com/issues/172227346#comment6

because the only guarantee which data=ordered provides is the security guarantee that stale data won't be revealed.

Yes, it's bad and breaks prefix append consistency, and does not match the documentation...

[ Parent | on HN ]
Re:I tested four NVMe SSDs from four vendors – half lose FLU... by fulafel on Wednesday November 22, 2023 @10:20AM (#38380405)
For more context, that's a comment from one of the ext4 main authors, Ted Ts'o. the other subsequent comment from him spells out the case more but sadly no spelled out NUL byte origin story I spotted from skimming.
[ Parent | on HN ]
Re:I tested four NVMe SSDs from four vendors – half lose FLU... by charleshn on Thursday November 30, 2023 @05:53PM (#38480392)
The original report [0] shows the corruption due to NUL bytes at the end of the file (see the hexdump). This comment [1] from Ted Ts'o details the exact chain of events leading to it.

[0] https://issuetracker.google.com/issues/172227346 [1] https://issuetracker.google.com/issues/172227346#comment8

[ Parent | on HN ]