The pmem driver don't 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.
Signed-off-by: Robert Elliott <[email protected]>
---
drivers/nvdimm/bus.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index a64023690cad..87762afa45b0 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -566,14 +566,17 @@ int nvdimm_revalidate_disk(struct gendisk *disk)
{
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;
--
2.14.3
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