Ts'o: Delayed allocation and the zero-length file problem

Posted Mar 16, 2009 21:23 UTC (Mon) by njs (subscriber, #40338)
In reply to: Ts'o: Delayed allocation and the zero-length file problem by masoncl
Parent article: Ts'o: Delayed allocation and the zero-length file problem

...Is what you're saying that for btrfs, metadata about extents (like disk location and checksums, I guess) is handled separately from metadata about filenames, and traditionally only the former had data=ordered-style guarantees? (Just trying to see if I understand.)

to post comments

Ts'o: Delayed allocation and the zero-length file problem

Posted Mar 16, 2009 22:51 UTC (Mon) by masoncl (subscriber, #47138) [Link] (1 responses)

That's correct. The main point behind data=ordered is to make sure that if you crash you don't have extent pointers in the file pointing to extents that haven't been written since they were allocated.

Without data=ordered, after a crash the file could have garbage in it, or bits of old files that had been deleted.

Ts'o: Delayed allocation and the zero-length file problem

Posted Mar 16, 2009 22:56 UTC (Mon) by njs (subscriber, #40338) [Link]

That makes sense. Thanks.