Allow ZNS NVMe SSDs to present a read-only namespace when append is not supported, instead of rejecting the namespace directly. This allows (i) the namespace to be used in read-only mode, which is not a problem as the append command only affects the write path, and (ii) to use standard management tools such as nvme-cli to choose a different format or firmware slot that is compatible with the Linux zoned block device. This patch includes comments from Christoph, Niklas and Keith that applied to a different approach setting capacity to 0 https://www.spinics.net/lists/linux-block/msg60747.html The reminder of the original patch will be submitted separately. Changes since V1: - Change logic to use NVME_NS_ATTR_RO (from Christoph) - Set max_zone_append egen in RO. This allows the device to be properly revalidated and enables user-space tools such as blkzone to be used when interacting with this zoned device. Signed-off-by: Javier González <javier.gonz@xxxxxxxxxxx> --- drivers/nvme/host/core.c | 3 ++- drivers/nvme/host/nvme.h | 1 + drivers/nvme/host/zns.c | 4 ++-- 3 files changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 40ca71b29bb9..4fcaec0b330b 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -2058,7 +2058,8 @@ static void nvme_update_disk_info(struct gendisk *disk, nvme_config_discard(disk, ns); nvme_config_write_zeroes(disk, ns); - if (id->nsattr & NVME_NS_ATTR_RO) + if (id->nsattr & NVME_NS_ATTR_RO || + test_bit(NVME_NS_FORCE_RO, &ns->flags)) set_disk_ro(disk, true); else set_disk_ro(disk, false); diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index bc330bf0d3bd..3a985e98ca27 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -448,6 +448,7 @@ struct nvme_ns { #define NVME_NS_REMOVING 0 #define NVME_NS_DEAD 1 #define NVME_NS_ANA_PENDING 2 +#define NVME_NS_FORCE_RO 3 struct nvme_fault_inject fault_inject; diff --git a/drivers/nvme/host/zns.c b/drivers/nvme/host/zns.c index 67e87e9f306f..8f3632c4db05 100644 --- a/drivers/nvme/host/zns.c +++ b/drivers/nvme/host/zns.c @@ -57,10 +57,10 @@ int nvme_update_zone_info(struct nvme_ns *ns, unsigned lbaf) /* Driver requires zone append support */ if (!(le32_to_cpu(log->iocs[nvme_cmd_zone_append]) & NVME_CMD_EFFECTS_CSUPP)) { + set_bit(NVME_NS_FORCE_RO, &ns->flags); dev_warn(ns->ctrl->device, - "append not supported for zoned namespace:%d\n", + "append not supported for zoned namespace:%d. Forcing to read-only mode\n", ns->head->ns_id); - return -EINVAL; } /* Lazily query controller append limit for the first zoned namespace */ -- 2.17.1
