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linvdimm, pmem: Preserve read-only setting for pmem devices

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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>
This commit is contained in:
Robert Elliott 2018-05-31 18:36:36 -05:00 committed by Greg Kroah-Hartman
parent f723101e1c
commit 37e875042f
1 changed files with 9 additions and 5 deletions
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14
drivers/nvdimm/bus.c
View File

@ -237,14 +237,18 @@ int nvdimm_revalidate_disk(struct gendisk *disk)
{
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;