From d9b0ebbe824469d178a05b0fb9004e4afce86009 Mon Sep 17 00:00:00 2001 From: Etienne Dechamps Date: Sun, 24 Feb 2013 11:22:07 +0000 Subject: Remove the bio_empty_barrier() check. To determine whether the kernel is capable of handling empty barrier BIOs, we check for the presence of the bio_empty_barrier() macro, which was introduced in 2.6.24. If this macro is defined, then we can flush disk vdevs; if it isn't, then flushing is disabled. Unfortunately, the bio_empty_barrier() macro was removed in 2.6.37, even though the kernel is still capable of handling empty barrier BIOs. As a result, flushing is effectively disabled on kernels >= 2.6.37, meaning that starting from this kernel version, zfs doesn't use barriers to guarantee on-disk data consistency. This is quite bad and can lead to potential data corruption on power failures. This patch fixes the issue by removing the configure check for bio_empty_barrier(), as we don't support kernels <= 2.6.24 anymore. Thanks to Richard Kojedzinszky for catching this nasty bug. Signed-off-by: Brian Behlendorf Closes #1318 --- module/zfs/vdev_disk.c | 9 --------- 1 file changed, 9 deletions(-) (limited to 'module/zfs/vdev_disk.c') diff --git a/module/zfs/vdev_disk.c b/module/zfs/vdev_disk.c index cbf0a4d4f..e902a70e1 100644 --- a/module/zfs/vdev_disk.c +++ b/module/zfs/vdev_disk.c @@ -604,8 +604,6 @@ vdev_disk_physio(struct block_device *bdev, caddr_t kbuf, return __vdev_disk_physio(bdev, NULL, kbuf, size, offset, flags); } -/* 2.6.24 API change */ -#ifdef HAVE_BIO_EMPTY_BARRIER BIO_END_IO_PROTO(vdev_disk_io_flush_completion, bio, size, rc) { zio_t *zio = bio->bi_private; @@ -646,13 +644,6 @@ vdev_disk_io_flush(struct block_device *bdev, zio_t *zio) return 0; } -#else -static int -vdev_disk_io_flush(struct block_device *bdev, zio_t *zio) -{ - return ENOTSUP; -} -#endif /* HAVE_BIO_EMPTY_BARRIER */ static int vdev_disk_io_start(zio_t *zio) -- cgit v1.2.3