I noticed that dm-snap reloads DM table of target mapped-device, which
fails for dax-capable device after dax support is added. Ideally,
adding dax support to dm-snap solves the issue, but it cannot be done
easily. This patch-set allows dm-snap to work with dax-capable target
devices when bio-based operation is used.
dax operation is unsupported with dm-snap, such that:
a) After snapshot is taken, mount with dax option to a target device
or a snapshot device fails. They can be mounted without dax.
b) After snapshot is taken to a dax-mounted target device, any writes
to the target device fails (EIO).
b) can be protected by changing lvcreate to fail when snapshot is
requested to a dax-mounted target device.
- Patch 1 solves an error when lvremove is made to a snapshot device.
- Patch 2 solves an error when lvcreate --snapshot is made to a dax-
capable device.
---
Toshi Kani (2):
1/2 dm: update table type check for dax
2/2 dm snap: add fake origin_direct_access
---
drivers/md/dm-ioctl.c | 11 ++++++++++-
drivers/md/dm-snap.c | 8 ++++++++
2 files changed, 18 insertions(+), 1 deletion(-)
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