Reliable, fast rename replacements

Posted Apr 3, 2009 21:43 UTC (Fri) by spitzak (guest, #4593)
In reply to: Reliable, fast rename replacements by butlerm
Parent article: From ext3 to ext4: An Interview with Theodore Ts'o (Linux Magazine)

This sounds like the correct solution to me and perhaps it is interesting and "pure" enough that Tso would feel like doing it.

My opinion on this: POSIX guarantees if you write & close a file and rename it, anybody trying to open the destination name will either see the old data or the new data, not anything else (such as an empty file). POSIX says "I don't guarantee anything on a crash". But the whole point of ext4 is to "guarantee" something. I do not see any logical reason for this guarantee to be something other than what POSIX guarantees while it is running. So the current behavior of ext4 on a crash is wrong.