tree b864418f5ba692535f619b7fd38dc7cf4960f830
parent 6dcfb751c927879399e404b3885cbdef7d8d368b
author Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 1304438471 -0400
committer Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 1305204963 -0400

xen-blkfront: Introduce BLKIF_OP_FLUSH_DISKCACHE support.

If the backend supports the 'feature-flush-cache' mode, use that
instead of the 'feature-barrier' support.

Currently there are three backends that support the 'feature-flush-cache'
mode: NetBSD, Solaris and Linux kernel. The 'flush' option is much
light-weight version than the 'barrier' support so lets try to use as
there are no filesystems in the kernel that use full barriers anymore.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>