coda: remove CODA_STORE/CODA_RELEASE upcalls

This is an variation on the patch sent by Christoph Hellwig which kills
file_count abuse by the Coda kernel module by moving the coda_flush
functionality into coda_release.  However part of reason we were using the
coda_flush callback was to allow Coda to pass errors that occur during
writeback from the userspace cache manager back to close().

As Al Viro explained on linux-fsdevel, it is impossible to guarantee that
such errors can in fact be returned back to the caller.  There are many
cases where the last reference to a file is not released by the close
system call and it is also impossible to pick some close as a 'last-close'
and delay it until all other references have been destroyed.

The CODA_STORE/CODA_RELEASE upcall combination is clearly a broken design,
and it is better to remove it completely.

Signed-off-by: Jan Harkes <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
5 files changed