On Fri, May 10, 2019 at 8:53 AM Pankaj Gupta <pagupta(a)redhat.com> wrote:
This patch adds 'DAXDEV_SYNC' flag which is set
for nd_region doing synchronous flush. This later
is used to disable MAP_SYNC functionality for
ext4 & xfs filesystem for devices don't support
synchronous flush.
Signed-off-by: Pankaj Gupta <pagupta(a)redhat.com>
---
drivers/dax/bus.c | 2 +-
drivers/dax/super.c | 13 ++++++++++++-
drivers/md/dm.c | 3 ++-
drivers/nvdimm/pmem.c | 5 ++++-
drivers/nvdimm/region_devs.c | 7 +++++++
include/linux/dax.h | 8 ++++++--
include/linux/libnvdimm.h | 1 +
7 files changed, 33 insertions(+), 6 deletions(-)
[..]
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 043f0761e4a0..ee007b75d9fd 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1969,7 +1969,8 @@ static struct mapped_device *alloc_dev(int minor)
sprintf(md->disk->disk_name, "dm-%d", minor);
if (IS_ENABLED(CONFIG_DAX_DRIVER)) {
- dax_dev = alloc_dax(md, md->disk->disk_name, &dm_dax_ops);
+ dax_dev = alloc_dax(md, md->disk->disk_name, &dm_dax_ops,
+ DAXDEV_F_SYNC);
Apologies for not realizing this until now, but this is broken.
Imaging a device-mapper configuration composed of both 'async'
virtio-pmem and 'sync' pmem. The 'sync' flag needs to be unified
across all members. I would change this argument to '0' and then
arrange for it to be set at dm_table_supports_dax() time after
validating that all components support synchronous dax.