-----Original Message----- From: oceanhehy(a)gmail.com <oceanhehy(a)gmail.com&gt; Sent: Tuesday, September 11, 2018 4:31 PM To: dan.j.williams(a)intel.com; vishal.l.verma(a)intel.com; qi.fuli(a)jp.fujitsu.com; linux-nvdimm(a)lists.01.org Cc: Ocean HY1 He <hehy1(a)lenovo.com&gt; Subject: [External] [ndctl PATCH] ndctl: recover from failed namespace creation From: Ocean He <hehy1(a)lenovo.com&gt; When namespace creation failure occurs, the consumed namespace (seed or 0th idle) and pfn/dax seed would block next namespace creation. A recovery is needed to handle this type failure. A symptom example (section size is 128MB) based on kernel 4.19-rc2 and ndctl v62: # ndctl create-namespace -r region1 -s 100m -t pmem -m fsdax { "dev":"namespace1.0", "mode":"fsdax", "map":"dev", "size":"96.00 MiB (100.66 MB)", "uuid":"ef9a0556-a610-40b5-8c71-43991765a2cc", "raw_uuid":"177b22e2-b7e8-482f-a063-2b8de876d979", "sector_size":512, "blockdev":"pmem1", "numa_node":1 } # ndctl create-namespace -r region1 -s 100m -t pmem -m fsdax libndctl: ndctl_pfn_enable: pfn1.1: failed to enable Error: namespace1.1: failed to enable failed to create namespace: No such device or address # ndctl destroy-namespace namespace1.0 -f destroyed 1 namespace # ndctl create-namespace -r region1 -s 128m -t pmem -m fsdax failed to create namespace: Device or resource busy Signed-off-by: Ocean He <hehy1(a)lenovo.com&gt; --- Additional information: A kernel patch to fix this has been reviewed by Dan Williams, and he prefers to handle it in ndctl directly. https://www.spinics.net/lists/kernel/msg2901465.html ndctl/namespace.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/ndctl/namespace.c b/ndctl/namespace.c index 510553c..76ee2ed 100644 --- a/ndctl/namespace.c +++ b/ndctl/namespace.c @@ -393,6 +393,8 @@ static int setup_namespace(struct ndctl_region *region, try(ndctl_pfn, set_align, pfn, p->align); try(ndctl_pfn, set_namespace, pfn, ndns); rc = ndctl_pfn_enable(pfn); + if (rc) + ndctl_pfn_set_namespace(pfn, NULL); } else if (p->mode == NDCTL_NS_MODE_DAX) { struct ndctl_dax *dax = ndctl_region_get_dax_seed(region); @@ -402,6 +404,8 @@ static int setup_namespace(struct ndctl_region *region, try(ndctl_dax, set_align, dax, p->align); try(ndctl_dax, set_namespace, dax, ndns); rc = ndctl_dax_enable(dax); + if (rc) + ndctl_dax_set_namespace(dax, NULL); } else if (p->mode == NDCTL_NS_MODE_SAFE) { struct ndctl_btt *btt = ndctl_region_get_btt_seed(region); @@ -783,7 +787,13 @@ static int namespace_create(struct ndctl_region *region) return -ENODEV; } - return setup_namespace(region, ndns, &p); + rc = setup_namespace(region, ndns, &p); + if (rc) { + ndctl_namespace_set_enforce_mode(ndns, NDCTL_NS_MODE_RAW); + ndctl_namespace_delete(ndns); + } + + return rc; } static int zero_info_block(struct ndctl_namespace *ndns) -- 1.8.3.1