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* [PATCH 0/3] libnvdimm: reset seeds for next namespace creation
@ 2018-09-10  6:21 Ocean He
  2018-09-10  6:21 ` [PATCH 1/3] libnvdimm, claim: remove static attribute of nd_detach_and_reset Ocean He
                   ` (3 more replies)
  0 siblings, 4 replies; 8+ messages in thread
From: Ocean He @ 2018-09-10  6:21 UTC (permalink / raw)
  To: dan.j.williams, zwisler, vishal.l.verma, dave.jiang
  Cc: Ocean He, linux-kernel, linux-nvdimm

From: Ocean He <hehy1@lenovo.com>

When pmem namespaces created are smaller than section size twice, the
second creation would fail and meanwhile there is a kernel call trace
which comes from commit 15d36fecd0bdc7510b70 ("mm: disallow mappings that
conflict for devm_memremap_pages()").
	------------[ cut here ]------------
	nd_pmem pfn1.1: Conflicting mapping in same section
	WARNING: CPU: 84 PID: 51974 at kernel/memremap.c:194 devm_memremap_pages+0x4a0/0x4e0
	CPU: 84 PID: 51974 Comm: ndctl Kdump: loaded Tainted: G W E 4.19.0-rc2-23-default+ #27
	RIP: 0010:devm_memremap_pages+0x4a0/0x4e0
	Call Trace:
	 pmem_attach_disk+0x3ab/0x581 [nd_pmem]
	 nvdimm_bus_probe+0x69/0x150 [libnvdimm]
	 really_probe+0x262/0x3d0
	 driver_probe_device+0x60/0x120
	 bind_store+0x102/0x190
	 kernfs_fop_write+0x105/0x180
	 __vfs_write+0x36/0x1a0
	 ? common_file_perm+0x47/0x130
	 ? security_file_permission+0x2c/0xb0
	 vfs_write+0xad/0x1a0
	 ksys_write+0x52/0xc0
	 do_syscall_64+0x5b/0x180
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Here is an example (section size is 128MB) based on kernel 4.19-rc2.
	# 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

When above second creation failure occurs, the expectation is to destroy
namespace1.0 to create a new namespace which size is aligned with section
size. However, both namespace seed and pfn seed have been consumed, the
new namespace creation still fails.
	# 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

To ensure pfn_seed/dax_seed and namespace_seed are always ready for next
namespace creation, this patch set enables seed detach and reset. Back to
the example, the new namespace creation never fails if this patch set
applied.
	# ndctl destroy-namespace namespace1.0 -f
	destroyed 1 namespace
	# ndctl create-namespace -r region1 -s 128m -t pmem -m fsdax
	{
	  "dev":"namespace1.0",
	  "mode":"fsdax",
	  "map":"dev",
	  "size":"124.00 MiB (130.02 MB)",
	  "uuid":"0d0e7506-d108-4a88-824a-edef26fd0399",
	  "raw_uuid":"efeb9647-12f5-44cd-8a52-2f3a0d14589a",
	  "sector_size":512,
	  "blockdev":"pmem1",
	  "numa_node":1
	}
	# ndctl create-namespace -r region1 -s 128m -t pmem -m fsdax
	{
 	  "dev":"namespace1.1",
 	  "mode":"fsdax",
 	  "map":"dev",
 	  "size":130023424,
 	  "uuid":"689828dc-8779-434d-8e93-0406d4e1e536",
 	  "raw_uuid":"d86e1025-c224-48b6-b2a7-6ccef152d5fd",
 	  "sector_size":512,
 	  "blockdev":"pmem1.1",
 	  "numa_node":1
	}

The mode devdax (-m devdax) has the same issue, this patch set could
cover it.

Ocean He (3):
  libnvdimm, claim: remove static attribute of nd_detach_and_reset
  libnvdimm, namespace_devs: add function nd_region_reset_ns_seed for
    namespace seed reset
  libnvdimm, region_devs: reset related seeds when fail to create
    namespace

 drivers/nvdimm/claim.c          |  2 +-
 drivers/nvdimm/namespace_devs.c | 32 ++++++++++++++++++++++++++++++++
 drivers/nvdimm/nd-core.h        |  2 ++
 drivers/nvdimm/region_devs.c    | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 69 insertions(+), 1 deletion(-)

-- 
1.8.3.1

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^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 1/3] libnvdimm, claim: remove static attribute of nd_detach_and_reset
  2018-09-10  6:21 [PATCH 0/3] libnvdimm: reset seeds for next namespace creation Ocean He
@ 2018-09-10  6:21 ` Ocean He
  2018-09-10  6:21 ` [PATCH 2/3] libnvdimm, namespace_devs: add function nd_region_reset_ns_seed for namespace seed reset Ocean He
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 8+ messages in thread
From: Ocean He @ 2018-09-10  6:21 UTC (permalink / raw)
  To: dan.j.williams, zwisler, vishal.l.verma, dave.jiang
  Cc: Ocean He, linux-kernel, linux-nvdimm

From: Ocean He <hehy1@lenovo.com>

The function nd_detach_and_reset needs to be called externally, so
remove the static attribute and declare it in nd-core.h.

Signed-off-by: Ocean He <hehy1@lenovo.com>
---
 drivers/nvdimm/claim.c   | 2 +-
 drivers/nvdimm/nd-core.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
index fb667bf..46e56ecf 100644
--- a/drivers/nvdimm/claim.c
+++ b/drivers/nvdimm/claim.c
@@ -117,7 +117,7 @@ struct nd_pfn *to_nd_pfn_safe(struct device *dev)
 	return NULL;
 }
 
-static void nd_detach_and_reset(struct device *dev,
+void nd_detach_and_reset(struct device *dev,
 		struct nd_namespace_common **_ndns)
 {
 	/* detach the namespace and destroy / reset the device */
diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index ac68072..7fd74d0 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -123,6 +123,7 @@ struct resource *nsblk_add_resource(struct nd_region *nd_region,
 resource_size_t __nvdimm_namespace_capacity(struct nd_namespace_common *ndns);
 void nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns);
 void __nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns);
+void nd_detach_and_reset(struct device *dev, struct nd_namespace_common **_ndns);
 bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
 		struct nd_namespace_common **_ndns);
 bool __nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
-- 
1.8.3.1

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^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 2/3] libnvdimm, namespace_devs: add function nd_region_reset_ns_seed for namespace seed reset
  2018-09-10  6:21 [PATCH 0/3] libnvdimm: reset seeds for next namespace creation Ocean He
  2018-09-10  6:21 ` [PATCH 1/3] libnvdimm, claim: remove static attribute of nd_detach_and_reset Ocean He
@ 2018-09-10  6:21 ` Ocean He
  2018-09-10  6:21 ` [PATCH 3/3] libnvdimm, region_devs: reset related seeds when fail to create namespace Ocean He
  2018-09-11  0:50 ` [PATCH 0/3] libnvdimm: reset seeds for next namespace creation Dan Williams
  3 siblings, 0 replies; 8+ messages in thread
From: Ocean He @ 2018-09-10  6:21 UTC (permalink / raw)
  To: dan.j.williams, zwisler, vishal.l.verma, dave.jiang
  Cc: Ocean He, linux-kernel, linux-nvdimm

From: Ocean He <hehy1@lenovo.com>

During runtime, if a namespace seed is used for new namespace creation
but fail, then it needs to be reset for next namespace creation.

Add function nd_region_reset_ns_seed for namespace seed reset and
declare it in nd-core.h.

Signed-off-by: Ocean He <hehy1@lenovo.com>
---
 drivers/nvdimm/namespace_devs.c | 32 ++++++++++++++++++++++++++++++++
 drivers/nvdimm/nd-core.h        |  1 +
 2 files changed, 33 insertions(+)

diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 4a42662..6678bbe 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -2129,6 +2129,38 @@ void nd_region_create_ns_seed(struct nd_region *nd_region)
 		nd_device_register(nd_region->ns_seed);
 }
 
+void nd_region_reset_ns_seed(struct nd_region *nd_region)
+{
+	struct device *dev = nd_region->ns_seed;
+	unsigned long long val = 0;
+	ssize_t rc;
+	u8 **uuid = NULL;
+
+	rc = __holder_class_store(dev, "");
+	dev_dbg(dev, "%s(%zd)\n", rc < 0 ? "fail to reset claim_class " : "", rc);
+
+	rc = __size_store(dev, val);
+	if (rc >= 0)
+		rc = nd_namespace_label_update(nd_region, dev);
+	dev_dbg(dev, "%s(%zd)\n", rc < 0 ? "fail to reset size " : "", rc);
+
+	if (is_namespace_pmem(dev)) {
+		struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
+
+		uuid = &nspm->uuid;
+	} else if (is_namespace_blk(dev)) {
+		struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);
+
+		uuid = &nsblk->uuid;
+	}
+
+	if (rc == 0 && val == 0 && uuid) {
+		/* setting size zero == 'delete namespace' */
+		kfree(*uuid);
+		*uuid = NULL;
+	}
+}
+
 void nd_region_create_dax_seed(struct nd_region *nd_region)
 {
 	WARN_ON(!is_nvdimm_bus_locked(&nd_region->dev));
diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index 7fd74d0..3ec6909 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -81,6 +81,7 @@ static inline bool is_memory(struct device *dev)
 void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev);
 struct nd_region;
 void nd_region_create_ns_seed(struct nd_region *nd_region);
+void nd_region_reset_ns_seed(struct nd_region *nd_region);
 void nd_region_create_btt_seed(struct nd_region *nd_region);
 void nd_region_create_pfn_seed(struct nd_region *nd_region);
 void nd_region_create_dax_seed(struct nd_region *nd_region);
-- 
1.8.3.1

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^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 3/3] libnvdimm, region_devs: reset related seeds when fail to create namespace
  2018-09-10  6:21 [PATCH 0/3] libnvdimm: reset seeds for next namespace creation Ocean He
  2018-09-10  6:21 ` [PATCH 1/3] libnvdimm, claim: remove static attribute of nd_detach_and_reset Ocean He
  2018-09-10  6:21 ` [PATCH 2/3] libnvdimm, namespace_devs: add function nd_region_reset_ns_seed for namespace seed reset Ocean He
@ 2018-09-10  6:21 ` Ocean He
  2018-09-11  0:40   ` kbuild test robot
  2018-09-11  0:40   ` [RFC PATCH] libnvdimm, region_devs: nd_region_detach_and_reset() can be static kbuild test robot
  2018-09-11  0:50 ` [PATCH 0/3] libnvdimm: reset seeds for next namespace creation Dan Williams
  3 siblings, 2 replies; 8+ messages in thread
From: Ocean He @ 2018-09-10  6:21 UTC (permalink / raw)
  To: dan.j.williams, zwisler, vishal.l.verma, dave.jiang
  Cc: Ocean He, linux-kernel, linux-nvdimm

From: Ocean He <hehy1@lenovo.com>

During runtime, namespace creation may fail if blocked by
commit 15d36fecd0bdc7510b70 ("mm: disallow mappings that conflict for
devm_memremap_pages()"). To ensure pfn_seed/dax_seed and namespace_seed
are ready for next namespace creation, here to do detach and reset.

Signed-off-by: Ocean He <hehy1@lenovo.com>
---
 drivers/nvdimm/region_devs.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index fa37afc..4c46fb6 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -703,7 +703,27 @@ void nd_mapping_free_labels(struct nd_mapping *nd_mapping)
 		kfree(label_ent);
 	}
 }
+/*
+ * To ensure pfn_seed/dax_seed and namespace_seed are ready for
+ * next namespace creation, here to do detach and reset.
+ */
+void nd_region_detach_and_reset(struct device *dev,
+		struct nd_region *nd_region)
+{
+	/* Only nd_pmem has been verified, fix me for other dev type. */
+	if (!is_nd_pmem(&nd_region->dev))
+		return;
 
+	if (is_nd_pfn(dev) || is_nd_dax(dev)) {
+		struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
+		struct nd_namespace_common *ndns = to_ndns(nd_region->ns_seed);
+
+		if (nd_pfn->ndns == ndns && ndns->claim == dev) {
+			nd_detach_and_reset(dev, &nd_pfn->ndns);
+			nd_region_reset_ns_seed(nd_region);
+			}
+	}
+}
 /*
  * Upon successful probe/remove, take/release a reference on the
  * associated interleave set (if present), and plant new btt + namespace
@@ -774,6 +794,20 @@ static void nd_region_notify_driver_action(struct nvdimm_bus *nvdimm_bus,
 			nd_region_create_ns_seed(nd_region);
 		nvdimm_bus_unlock(dev);
 	}
+	if (is_nd_pfn(dev) && !probe) {
+		nd_region = to_nd_region(dev->parent);
+		nvdimm_bus_lock(dev);
+		if (nd_region->pfn_seed == dev)
+			nd_region_detach_and_reset(dev, nd_region);
+		nvdimm_bus_unlock(dev);
+	}
+	if (is_nd_dax(dev) && !probe) {
+		nd_region = to_nd_region(dev->parent);
+		nvdimm_bus_lock(dev);
+		if (nd_region->dax_seed == dev)
+			nd_region_detach_and_reset(dev, nd_region);
+		nvdimm_bus_unlock(dev);
+	}
 }
 
 void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev)
-- 
1.8.3.1

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^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 3/3] libnvdimm, region_devs: reset related seeds when fail to create namespace
  2018-09-10  6:21 ` [PATCH 3/3] libnvdimm, region_devs: reset related seeds when fail to create namespace Ocean He
@ 2018-09-11  0:40   ` kbuild test robot
  2018-09-11  0:40   ` [RFC PATCH] libnvdimm, region_devs: nd_region_detach_and_reset() can be static kbuild test robot
  1 sibling, 0 replies; 8+ messages in thread
From: kbuild test robot @ 2018-09-11  0:40 UTC (permalink / raw)
  To: Ocean He; +Cc: linux-nvdimm, Ocean He, linux-kernel, kbuild-all, zwisler

Hi Ocean,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linux-nvdimm/libnvdimm-for-next]
[also build test WARNING on v4.19-rc3 next-20180910]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Ocean-He/libnvdimm-reset-seeds-for-next-namespace-creation/20180911-005505
base:   https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git libnvdimm-for-next
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)

   drivers/nvdimm/region_devs.c:84:29: sparse: expression using sizeof(void)
   drivers/nvdimm/region_devs.c:84:29: sparse: expression using sizeof(void)
   drivers/nvdimm/region_devs.c:405:37: sparse: expression using sizeof(void)
   drivers/nvdimm/region_devs.c:405:37: sparse: expression using sizeof(void)
>> drivers/nvdimm/region_devs.c:710:6: sparse: symbol 'nd_region_detach_and_reset' was not declared. Should it be static?
   drivers/nvdimm/region_devs.c:1127:31: sparse: expression using sizeof(void)
   drivers/nvdimm/region_devs.c:985:9: sparse: context imbalance in 'nd_region_acquire_lane' - wrong count at exit
   drivers/nvdimm/region_devs.c:998:36: sparse: context imbalance in 'nd_region_release_lane' - unexpected unlock

Please review and possibly fold the followup patch.

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
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^ permalink raw reply	[flat|nested] 8+ messages in thread

* [RFC PATCH] libnvdimm, region_devs: nd_region_detach_and_reset() can be static
  2018-09-10  6:21 ` [PATCH 3/3] libnvdimm, region_devs: reset related seeds when fail to create namespace Ocean He
  2018-09-11  0:40   ` kbuild test robot
@ 2018-09-11  0:40   ` kbuild test robot
  1 sibling, 0 replies; 8+ messages in thread
From: kbuild test robot @ 2018-09-11  0:40 UTC (permalink / raw)
  To: Ocean He; +Cc: linux-nvdimm, Ocean He, linux-kernel, kbuild-all, zwisler


Fixes: 39ac5d361db2 ("libnvdimm, region_devs: reset related seeds when fail to create namespace")
Signed-off-by: kbuild test robot <fengguang.wu@intel.com>
---
 region_devs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 4c46fb6..a2f667e 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -707,7 +707,7 @@ void nd_mapping_free_labels(struct nd_mapping *nd_mapping)
  * To ensure pfn_seed/dax_seed and namespace_seed are ready for
  * next namespace creation, here to do detach and reset.
  */
-void nd_region_detach_and_reset(struct device *dev,
+static void nd_region_detach_and_reset(struct device *dev,
 		struct nd_region *nd_region)
 {
 	/* Only nd_pmem has been verified, fix me for other dev type. */
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* Re: [PATCH 0/3] libnvdimm: reset seeds for next namespace creation
  2018-09-10  6:21 [PATCH 0/3] libnvdimm: reset seeds for next namespace creation Ocean He
                   ` (2 preceding siblings ...)
  2018-09-10  6:21 ` [PATCH 3/3] libnvdimm, region_devs: reset related seeds when fail to create namespace Ocean He
@ 2018-09-11  0:50 ` Dan Williams
  2018-09-11  8:49   ` [External] " Ocean HY1 He
  3 siblings, 1 reply; 8+ messages in thread
From: Dan Williams @ 2018-09-11  0:50 UTC (permalink / raw)
  To: Ocean He; +Cc: Ocean He, linux-nvdimm, Linux Kernel Mailing List, zwisler

On Sun, Sep 9, 2018 at 11:21 PM, Ocean He <oceanhehy@gmail.com> wrote:
> From: Ocean He <hehy1@lenovo.com>
>
> When pmem namespaces created are smaller than section size twice, the
> second creation would fail and meanwhile there is a kernel call trace
> which comes from commit 15d36fecd0bdc7510b70 ("mm: disallow mappings that
> conflict for devm_memremap_pages()").
>         ------------[ cut here ]------------
>         nd_pmem pfn1.1: Conflicting mapping in same section
>         WARNING: CPU: 84 PID: 51974 at kernel/memremap.c:194 devm_memremap_pages+0x4a0/0x4e0
>         CPU: 84 PID: 51974 Comm: ndctl Kdump: loaded Tainted: G W E 4.19.0-rc2-23-default+ #27
>         RIP: 0010:devm_memremap_pages+0x4a0/0x4e0
>         Call Trace:
>          pmem_attach_disk+0x3ab/0x581 [nd_pmem]
>          nvdimm_bus_probe+0x69/0x150 [libnvdimm]
>          really_probe+0x262/0x3d0
>          driver_probe_device+0x60/0x120
>          bind_store+0x102/0x190
>          kernfs_fop_write+0x105/0x180
>          __vfs_write+0x36/0x1a0
>          ? common_file_perm+0x47/0x130
>          ? security_file_permission+0x2c/0xb0
>          vfs_write+0xad/0x1a0
>          ksys_write+0x52/0xc0
>          do_syscall_64+0x5b/0x180
>          entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> Here is an example (section size is 128MB) based on kernel 4.19-rc2.
>         # 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
>
> When above second creation failure occurs, the expectation is to destroy
> namespace1.0 to create a new namespace which size is aligned with section
> size. However, both namespace seed and pfn seed have been consumed, the
> new namespace creation still fails.
>         # 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
>
> To ensure pfn_seed/dax_seed and namespace_seed are always ready for next
> namespace creation, this patch set enables seed detach and reset. Back to
> the example, the new namespace creation never fails if this patch set
> applied.
>         # ndctl destroy-namespace namespace1.0 -f
>         destroyed 1 namespace
>         # ndctl create-namespace -r region1 -s 128m -t pmem -m fsdax
>         {
>           "dev":"namespace1.0",
>           "mode":"fsdax",
>           "map":"dev",
>           "size":"124.00 MiB (130.02 MB)",
>           "uuid":"0d0e7506-d108-4a88-824a-edef26fd0399",
>           "raw_uuid":"efeb9647-12f5-44cd-8a52-2f3a0d14589a",
>           "sector_size":512,
>           "blockdev":"pmem1",
>           "numa_node":1
>         }
>         # ndctl create-namespace -r region1 -s 128m -t pmem -m fsdax
>         {
>           "dev":"namespace1.1",
>           "mode":"fsdax",
>           "map":"dev",
>           "size":130023424,
>           "uuid":"689828dc-8779-434d-8e93-0406d4e1e536",
>           "raw_uuid":"d86e1025-c224-48b6-b2a7-6ccef152d5fd",
>           "sector_size":512,
>           "blockdev":"pmem1.1",
>           "numa_node":1
>         }
>
> The mode devdax (-m devdax) has the same issue, this patch set could
> cover it.

This is good analysis, but I believe this is better fixed / handled in
ndctl directly. This is just one of a few reasons that namespace
creation can fail, and it should be ndctl's job to recover from failed
creation. The kernel only provides the mechanism the policy of what to
do with errors and interrupted namespace creation is up to userspace.

Also, in the future, the plan is to allow namespaces smaller than a
section size which will fix this particular failing condition
properly.
_______________________________________________
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Linux-nvdimm@lists.01.org
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^ permalink raw reply	[flat|nested] 8+ messages in thread

* RE: [External]  Re: [PATCH 0/3] libnvdimm: reset seeds for next namespace creation
  2018-09-11  0:50 ` [PATCH 0/3] libnvdimm: reset seeds for next namespace creation Dan Williams
@ 2018-09-11  8:49   ` Ocean HY1 He
  0 siblings, 0 replies; 8+ messages in thread
From: Ocean HY1 He @ 2018-09-11  8:49 UTC (permalink / raw)
  To: Dan Williams, Ocean He; +Cc: linux-nvdimm, Linux Kernel Mailing List, zwisler



> -----Original Message-----
> From: Dan Williams <dan.j.williams@intel.com>
> Sent: Tuesday, September 11, 2018 8:51 AM
> To: Ocean He <oceanhehy@gmail.com>
> Cc: zwisler@kernel.org; Vishal L Verma <vishal.l.verma@intel.com>; Dave Jiang
> <dave.jiang@intel.com>; linux-nvdimm <linux-nvdimm@lists.01.org>; Linux
> Kernel Mailing List <linux-kernel@vger.kernel.org>; Ocean HY1 He
> <hehy1@lenovo.com>
> Subject: [External] Re: [PATCH 0/3] libnvdimm: reset seeds for next
> namespace creation
> 
> On Sun, Sep 9, 2018 at 11:21 PM, Ocean He <oceanhehy@gmail.com> wrote:
> > From: Ocean He <hehy1@lenovo.com>
> >
> > When pmem namespaces created are smaller than section size twice, the
> > second creation would fail and meanwhile there is a kernel call trace
> > which comes from commit 15d36fecd0bdc7510b70 ("mm: disallow mappings
> that
> > conflict for devm_memremap_pages()").
> >         ------------[ cut here ]------------
> >         nd_pmem pfn1.1: Conflicting mapping in same section
> >         WARNING: CPU: 84 PID: 51974 at kernel/memremap.c:194
> devm_memremap_pages+0x4a0/0x4e0
> >         CPU: 84 PID: 51974 Comm: ndctl Kdump: loaded Tainted: G W E 4.19.0-
> rc2-23-default+ #27
> >         RIP: 0010:devm_memremap_pages+0x4a0/0x4e0
> >         Call Trace:
> >          pmem_attach_disk+0x3ab/0x581 [nd_pmem]
> >          nvdimm_bus_probe+0x69/0x150 [libnvdimm]
> >          really_probe+0x262/0x3d0
> >          driver_probe_device+0x60/0x120
> >          bind_store+0x102/0x190
> >          kernfs_fop_write+0x105/0x180
> >          __vfs_write+0x36/0x1a0
> >          ? common_file_perm+0x47/0x130
> >          ? security_file_permission+0x2c/0xb0
> >          vfs_write+0xad/0x1a0
> >          ksys_write+0x52/0xc0
> >          do_syscall_64+0x5b/0x180
> >          entry_SYSCALL_64_after_hwframe+0x44/0xa9
> >
> > Here is an example (section size is 128MB) based on kernel 4.19-rc2.
> >         # 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
> >
> > When above second creation failure occurs, the expectation is to destroy
> > namespace1.0 to create a new namespace which size is aligned with section
> > size. However, both namespace seed and pfn seed have been consumed,
> the
> > new namespace creation still fails.
> >         # 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
> >
> > To ensure pfn_seed/dax_seed and namespace_seed are always ready for
> next
> > namespace creation, this patch set enables seed detach and reset. Back to
> > the example, the new namespace creation never fails if this patch set
> > applied.
> >         # ndctl destroy-namespace namespace1.0 -f
> >         destroyed 1 namespace
> >         # ndctl create-namespace -r region1 -s 128m -t pmem -m fsdax
> >         {
> >           "dev":"namespace1.0",
> >           "mode":"fsdax",
> >           "map":"dev",
> >           "size":"124.00 MiB (130.02 MB)",
> >           "uuid":"0d0e7506-d108-4a88-824a-edef26fd0399",
> >           "raw_uuid":"efeb9647-12f5-44cd-8a52-2f3a0d14589a",
> >           "sector_size":512,
> >           "blockdev":"pmem1",
> >           "numa_node":1
> >         }
> >         # ndctl create-namespace -r region1 -s 128m -t pmem -m fsdax
> >         {
> >           "dev":"namespace1.1",
> >           "mode":"fsdax",
> >           "map":"dev",
> >           "size":130023424,
> >           "uuid":"689828dc-8779-434d-8e93-0406d4e1e536",
> >           "raw_uuid":"d86e1025-c224-48b6-b2a7-6ccef152d5fd",
> >           "sector_size":512,
> >           "blockdev":"pmem1.1",
> >           "numa_node":1
> >         }
> >
> > The mode devdax (-m devdax) has the same issue, this patch set could
> > cover it.
> 
> This is good analysis, but I believe this is better fixed / handled in
> ndctl directly. This is just one of a few reasons that namespace
> creation can fail, and it should be ndctl's job to recover from failed
> creation. The kernel only provides the mechanism the policy of what to
> do with errors and interrupted namespace creation is up to userspace.
> 
Well, thanks for your review. I just send out the patch of ndctl for this
issue, please help to review again. Many thanks!
https://lists.01.org/pipermail/linux-nvdimm/2018-September/017778.html

Ocean.
> Also, in the future, the plan is to allow namespaces smaller than a
> section size which will fix this particular failing condition
> properly.
I am interesting that what minimal size is allowed for namespace creation.
I need this to guide the NVDIMM enablement on Lenovo ThinkSystem Servers.

I see function nvdimm_namespace_common_probe return error if size is less
than ND_MIN_NAMESPACE_SIZE(equals to PAGE_SIZE).
	size = nvdimm_namespace_capacity(ndns);
	if (size < ND_MIN_NAMESPACE_SIZE) {
		dev_dbg(&ndns->dev, "%pa, too small must be at least %#x\n",
				&size, ND_MIN_NAMESPACE_SIZE);
		return ERR_PTR(-ENODEV);
	}

I also see function nd_namespace_store return error if size is less than SZ_16M.
	if (__nvdimm_namespace_capacity(ndns) < SZ_16M) {
		dev_dbg(dev, "%s too small to host\n", name);
		len = -ENXIO;
		goto out_attach;
	}

Ocean.
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^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2018-09-11  8:50 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-09-10  6:21 [PATCH 0/3] libnvdimm: reset seeds for next namespace creation Ocean He
2018-09-10  6:21 ` [PATCH 1/3] libnvdimm, claim: remove static attribute of nd_detach_and_reset Ocean He
2018-09-10  6:21 ` [PATCH 2/3] libnvdimm, namespace_devs: add function nd_region_reset_ns_seed for namespace seed reset Ocean He
2018-09-10  6:21 ` [PATCH 3/3] libnvdimm, region_devs: reset related seeds when fail to create namespace Ocean He
2018-09-11  0:40   ` kbuild test robot
2018-09-11  0:40   ` [RFC PATCH] libnvdimm, region_devs: nd_region_detach_and_reset() can be static kbuild test robot
2018-09-11  0:50 ` [PATCH 0/3] libnvdimm: reset seeds for next namespace creation Dan Williams
2018-09-11  8:49   ` [External] " Ocean HY1 He

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