From a98f1946ea58a21ea8004e07d414ba2f99bc6434 Mon Sep 17 00:00:00 2001 From: Robert Elliott Date: Thu, 31 May 2018 18:36:36 -0500 Subject: [PATCH] linvdimm, pmem: Preserve read-only setting for pmem devices 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: Fixes: 581388209405 ("libnvdimm, nfit: handle unarmed dimms, mark namespaces read-only") Signed-off-by: Robert Elliott Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman --- drivers/nvdimm/bus.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c index baf283986a7e..2fffd42767c7 100644 --- a/drivers/nvdimm/bus.c +++ b/drivers/nvdimm/bus.c @@ -565,14 +565,18 @@ 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;