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>
{
struct device *dev = disk_to_dev(disk)->parent;
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;