Re: Subtle races between DAX mmap fault and write path
From: Keith Packard <keithp@keithp.com>
Date: 2016-08-01 03:31:34
Also in:
linux-ext4, linux-fsdevel, nvdimm
From: Keith Packard <keithp@keithp.com>
Date: 2016-08-01 03:31:34
Also in:
linux-ext4, linux-fsdevel, nvdimm
Dave Chinner [off-list ref] writes:
So we'd see that from the point of view of a torn single sector write. Ok, so we better limit DAX to CRC enabled filesystems to ensure these sorts of events are always caught by the filesystem.
Which is the same lack of guarantee that we already get on rotating media. Flash media seems to work harder to provide sector atomicity; I guess that's a feature? The alternative is to hide metadata behind a translation layer, and while that can be done for lame file systems, I'd like to see the raw hardware capabilities exposed and then make free software that constructs a reliable system on top of that. -- -keith