This series fixes a few issues that I found with DM's handling of DAX
devices. Here are some of the issues I found:
* We can create a dm-stripe or dm-linear device which is made up of an
fsdax PMEM namespace and a raw PMEM namespace but which can hold a
filesystem mounted with the -o dax mount option. DAX operations to
the raw PMEM namespace part lack struct page and can fail in
interesting/unexpected ways when doing things like fork(), examining
memory with gdb, etc.
* We can create a dm-stripe or dm-linear device which is made up of an
fsdax PMEM namespace and a BRD ramdisk which can hold a filesystem
mounted with the -o dax mount option. All I/O to this filesystem
will fail.
---
Changes since v2:
* Only set QUEUE_FLAG_DAX for fsdax mode PMEM namespaces. (Mike)
* Check for QUEUE_FLAG_DAX in __bdev_dax_supported(). (Mike)
* Get rid of DM_TYPE_DAX_BIO_BASED reworks. (Mike)
* Dropped the first 2 prep patches of v2 since they were merged for
v4.18-rc1. (Thanks, Darrick!)
---
Mike, can you take this series through your tree?
Personally I think this should be treated as a bug fix and merged in the
v4.18-rc* series.
Ross Zwisler (3):
pmem: only set QUEUE_FLAG_DAX for fsdax mode
dax: bdev_dax_supported() check for QUEUE_FLAG_DAX
dm: prevent DAX mounts if not supported
drivers/dax/super.c | 8 ++++++++
drivers/md/dm-ioctl.c | 5 +++++
drivers/md/dm-table.c | 7 +++----
drivers/md/dm.c | 3 +--
drivers/nvdimm/pmem.c | 3 ++-
include/linux/device-mapper.h | 5 +++++
6 files changed, 24 insertions(+), 7 deletions(-)
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2.14.4
