[PATCH] Make XFS workqueues nonfreezable

Since freezable workqueues are broken in 2.6.21-rc
(cf. http://marc.theaimsgroup.com/?l=linux-kernel&m=116855740612755,
http://marc.theaimsgroup.com/?l=linux-kernel&m=117261312523921&w=2)
it's better to change the only user of them, which is XFS, to use "normal"
nonfreezable workqueues.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: David Chinner <dgc@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>