blockdev: don't set S_DAX for misaligned partitions
commit f0b2e563bc419df7c1b3d2f494574c25125f6aed upstream.
The dax code doesn't currently support misaligned partitions,
so disable O_DIRECT via dax until such time as that support
materializes.
Suggested-by: Boaz Harrosh <boaz@plexistor.com>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/block_dev.c b/fs/block_dev.c
index c7e4163..ccfd31f 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1234,6 +1234,13 @@
goto out_clear;
}
bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
+ /*
+ * If the partition is not aligned on a page
+ * boundary, we can't do dax I/O to it.
+ */
+ if ((bdev->bd_part->start_sect % (PAGE_SIZE / 512)) ||
+ (bdev->bd_part->nr_sects % (PAGE_SIZE / 512)))
+ bdev->bd_inode->i_flags &= ~S_DAX;
}
} else {
if (bdev->bd_contains == bdev) {