4.4-stable review patch. If anyone has any objections, please let me know.
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From: Robert Elliott elliott@hpe.com
commit 254a4cd50b9fe2291a12b8902e08e56dcc4e9b10 upstream.
The pmem driver does not honor a forced read-only setting for very long: $ blockdev --setro /dev/pmem0 $ blockdev --getro /dev/pmem0 1
followed by various commands like these: $ blockdev --rereadpt /dev/pmem0 or $ mkfs.ext4 /dev/pmem0
results in this in the kernel serial log: nd_pmem namespace0.0: region0 read-write, marking pmem0 read-write
with the read-only setting lost: $ blockdev --getro /dev/pmem0 0
That's from bus.c nvdimm_revalidate_disk(), which always applies the setting from nd_region (which is initially based on the ACPI NFIT NVDIMM state flags not_armed bit).
In contrast, commit 20bd1d026aac ("scsi: sd: Keep disk read-only when re-reading partition") fixed this issue for SCSI devices to preserve the previous setting if it was set to read-only.
This patch modifies bus.c to preserve any previous read-only setting. It also eliminates the kernel serial log print except for cases where read-write is changed to read-only, so it doesn't print read-only to read-only non-changes.
Cc: stable@vger.kernel.org Fixes: 581388209405 ("libnvdimm, nfit: handle unarmed dimms, mark namespaces read-only") Signed-off-by: Robert Elliott elliott@hpe.com Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/nvdimm/bus.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
--- a/drivers/nvdimm/bus.c +++ b/drivers/nvdimm/bus.c @@ -237,14 +237,18 @@ int nvdimm_revalidate_disk(struct gendis { struct device *dev = disk->driverfs_dev; struct nd_region *nd_region = to_nd_region(dev->parent); - const char *pol = nd_region->ro ? "only" : "write"; + int disk_ro = get_disk_ro(disk);
- if (nd_region->ro == get_disk_ro(disk)) + /* + * Upgrade to read-only if the region is read-only preserve as + * read-only if the disk is already read-only. + */ + if (disk_ro || nd_region->ro == disk_ro) return 0;
- dev_info(dev, "%s read-%s, marking %s read-%s\n", - dev_name(&nd_region->dev), pol, disk->disk_name, pol); - set_disk_ro(disk, nd_region->ro); + dev_info(dev, "%s read-only, marking %s read-only\n", + dev_name(&nd_region->dev), disk->disk_name); + set_disk_ro(disk, 1);
return 0;