[PATCH 2/2] blockdev: don't set S_DAX for misaligned partitions
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(a)plexistor.com>
Signed-off-by: Jeff Moyer <jmoyer(a)redhat.com>
---
fs/block_dev.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1982437..1170f8c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1241,6 +1241,13 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode,
int for_part)
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) {
--
1.8.3.1