On Fri, Jan 7, 2011 at 5:32 PM, Massimo Maggi [off-list ref] wrote:

Are you suggesting to do:
1)fopen with O_TRUNC, O_ATOMIC: returns fd to a temporary file
2)application writes to that fd, with one or more system calls, in a
short time or in long time, at his will.
3)at fclose (or even at fsync ) atomically swap "data pointer" of "re=

al

file" with "temp file", then delete temp.In a transparent mode to
userland. =C2=A0(something similar to e4defrag).
Is this sum up correct?

Almost. Swap should probably not be done at fsync time.
Other open references (for example running executables) should be swapp=
ed too.

The new-file case has to be handled too.

Olaf
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" =
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html