tree 4d3a19c066d2e513f7d1645092b4a27059b5ee67
parent b9d128f1088ea5245109dfc9bbceb128b6371a77
author Christoph Hellwig <hch@lst.de> 1256822044 +0100
committer Jens Axboe <jens.axboe@oracle.com> 1256822044 +0100

blkdev: flush disk cache on ->fsync

Currently there is no barrier support in the block device code.  That
means we cannot guarantee any sort of data integerity when using the
block device node with dis kwrite caches enabled.  Using the raw block
device node is a typical use case for virtualization (and I assume
databases, too).  This patch changes block_fsync to issue a cache flush
and thus make fsync on block device nodes actually useful.

Note that in mainline we would also need to add such code to the
->aio_write method for O_SYNC handling, but assuming that Jan's patch
series for the O_SYNC rewrite goes in it will also call into ->fsync
for 2.6.32.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>