* [PATCH] nvme-list: fix verbose JSON output for 'nvme list' command
@ 2025-07-21 10:29 Nilay Shroff
2025-07-24 14:18 ` Daniel Wagner
0 siblings, 1 reply; 6+ messages in thread
From: Nilay Shroff @ 2025-07-21 10:29 UTC (permalink / raw)
To: linux-nvme; +Cc: dwagner, msmurthy, gjoyce
The verbose JSON output of the nvme list command is currently incorrect in
both multipath and non-multipath configurations. Specifically, it prints
empty Namespaces[] and Paths[] arrays in the wrong places, leading to
confusion and invalid output. For example, on a system with single NVMe
disk, signle controller and one namepsace created, 'nvme list --verbose
--output json' prints the following output:
With multipath disabled:
{
"Devices":[
{
...
"Subsystems":[
{
...
"Controllers":[
{
"Controller":"nvme0",
...
"Namespaces":[
{
"NameSpace":"nvme0n1",
...
}
],
"Paths":[] <---- Incorrct: Path should not be present
}
],
"Namespaces":[] <-----Incorrect: Namespaces should not be here
}
]
}
]
}
With multipath enabled, the output changes, but still has misplaced or
empty fields:
{
"Devices":[
{
...
"Subsystems":[
{
...
"Controllers":[
{
"Controller":"nvme0",
...
"Namespaces":[] <-----Incorrect: Namespaces should not be here
"Paths":[
{
"Path":"nvme0c0n1",
"ANAState":"optimized"
}
]
}
],
"Namespaces":[
{
"NameSpace":"nvme0n1",
...
}
]
}
]
}
]
}
So as we could see above in both multipath and non-multipath scenarios,
the JSON formatted output is incorrect.
The existing JSON formatting logic doesn't differentiate between multipath
and non-multipath configurations. As a result:
- "Paths" is printed even when multipath is disabled.
- "Namespaces" appear at incorrect levels in the output tree.
This patch updates the logic for verbose JSON output in nvme list to
properly reflect the system configuration:
- When multipath is enabled, each namespace entry includes its associated
paths and controller attributes.
- When multipath is disabled, namespaces are shown directly under the
controller, and the "Paths" array is omitted.
After this fix, JSON formatted output looks as below:
Scenario1: multipath is enabled
{
Devices: [
{
...
Subsystems: [
{
...
Namespaces: [
{
"NameSpace":"nvme0n1",
...
Paths: [
{
"Path":"nvme0c0n1",
"ANAState":"optimized",
"Controller":"nvme0",
...
}
]
}
]
}
]
}
]
}
Scenario2: multipath is disabled
{
Devices: [
{
...
Subsystems: [
{
...
Controllers: [
{
"Controller":"nvme0",
...
"Namespaces":[
{
"NameSpace":"nvme0n1",
...
}
]
}
]
}
]
}
]
}
This fix ensures the JSON output is semantically accurate and easier to
consume by tools that parse nvme list --verbose --output json.
Reported-by: Maram Srimannarayana Murthy <msmurthy@imap.linux.ibm.com>
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
---
nvme-print-json.c | 170 ++++++++++++++++++++++++++------------------
nvme-print-stdout.c | 12 ----
nvme.h | 12 ++++
3 files changed, 113 insertions(+), 81 deletions(-)
diff --git a/nvme-print-json.c b/nvme-print-json.c
index a4b8df9f..3d656baa 100644
--- a/nvme-print-json.c
+++ b/nvme-print-json.c
@@ -4423,6 +4423,103 @@ static void json_support_log(struct nvme_supported_log_pages *support_log,
json_print(r);
}
+static void json_print_detail_list_multipath(nvme_subsystem_t s,
+ struct json_object *jss)
+{
+ nvme_ns_t n;
+ nvme_path_t p;
+ struct json_object *jnss = json_create_array();
+
+ nvme_subsystem_for_each_ns(s, n) {
+ struct json_object *jns = json_create_object();
+ struct json_object *jpaths = json_create_array();
+
+ int lba = nvme_ns_get_lba_size(n);
+ uint64_t nsze = nvme_ns_get_lba_count(n) * lba;
+ uint64_t nuse = nvme_ns_get_lba_util(n) * lba;
+
+ obj_add_str(jns, "NameSpace", nvme_ns_get_name(n));
+ obj_add_str(jns, "Generic", nvme_ns_get_generic_name(n));
+ obj_add_int(jns, "NSID", nvme_ns_get_nsid(n));
+ obj_add_uint64(jns, "UsedBytes", nuse);
+ obj_add_uint64(jns, "MaximumLBA", nvme_ns_get_lba_count(n));
+ obj_add_uint64(jns, "PhysicalSize", nsze);
+ obj_add_int(jns, "SectorSize", lba);
+
+ nvme_namespace_for_each_path(n, p) {
+ nvme_ctrl_t c;
+ struct json_object *jpath = json_create_object();
+
+ obj_add_str(jpath, "Path", nvme_path_get_name(p));
+ obj_add_str(jpath, "ANAState", nvme_path_get_ana_state(p));
+
+ /*
+ * For multipath, each path maps to one controller.
+ * So get the controller from the path and then add
+ * controller attributes.
+ */
+ c = nvme_path_get_ctrl(p);
+ obj_add_str(jpath, "Controller", nvme_ctrl_get_name(c));
+ obj_add_str(jpath, "Cntlid", nvme_ctrl_get_cntlid(c));
+ obj_add_str(jpath, "SerialNumber", nvme_ctrl_get_serial(c));
+ obj_add_str(jpath, "ModelNumber", nvme_ctrl_get_model(c));
+ obj_add_str(jpath, "Firmware", nvme_ctrl_get_firmware(c));
+ obj_add_str(jpath, "Transport", nvme_ctrl_get_transport(c));
+ obj_add_str(jpath, "Address", nvme_ctrl_get_address(c));
+ obj_add_str(jpath, "Slot", nvme_ctrl_get_phy_slot(c));
+
+ array_add_obj(jpaths, jpath);
+ }
+
+ obj_add_obj(jns, "Paths", jpaths);
+ array_add_obj(jnss, jns);
+ }
+ obj_add_obj(jss, "Namespaces", jnss);
+}
+
+static void json_print_detail_list(nvme_subsystem_t s, struct json_object *jss)
+{
+ nvme_ctrl_t c;
+ nvme_ns_t n;
+ struct json_object *jctrls = json_create_array();
+
+ nvme_subsystem_for_each_ctrl(s, c) {
+ struct json_object *jctrl = json_create_object();
+ struct json_object *jnss = json_create_array();
+
+ obj_add_str(jctrl, "Controller", nvme_ctrl_get_name(c));
+ obj_add_str(jctrl, "Cntlid", nvme_ctrl_get_cntlid(c));
+ obj_add_str(jctrl, "SerialNumber", nvme_ctrl_get_serial(c));
+ obj_add_str(jctrl, "ModelNumber", nvme_ctrl_get_model(c));
+ obj_add_str(jctrl, "Firmware", nvme_ctrl_get_firmware(c));
+ obj_add_str(jctrl, "Transport", nvme_ctrl_get_transport(c));
+ obj_add_str(jctrl, "Address", nvme_ctrl_get_address(c));
+ obj_add_str(jctrl, "Slot", nvme_ctrl_get_phy_slot(c));
+
+ nvme_ctrl_for_each_ns(c, n) {
+ struct json_object *jns = json_create_object();
+ int lba = nvme_ns_get_lba_size(n);
+ uint64_t nsze = nvme_ns_get_lba_count(n) * lba;
+ uint64_t nuse = nvme_ns_get_lba_util(n) * lba;
+
+ obj_add_str(jns, "NameSpace", nvme_ns_get_name(n));
+ obj_add_str(jns, "Generic", nvme_ns_get_generic_name(n));
+ obj_add_int(jns, "NSID", nvme_ns_get_nsid(n));
+ obj_add_uint64(jns, "UsedBytes", nuse);
+ obj_add_uint64(jns, "MaximumLBA", nvme_ns_get_lba_count(n));
+ obj_add_uint64(jns, "PhysicalSize", nsze);
+ obj_add_int(jns, "SectorSize", lba);
+
+ array_add_obj(jnss, jns);
+ }
+
+ obj_add_obj(jctrl, "Namespaces", jnss);
+ array_add_obj(jctrls, jctrl);
+ }
+
+ obj_add_obj(jss, "Controllers", jctrls);
+}
+
static void json_detail_list(nvme_root_t t)
{
struct json_object *r = json_create_object();
@@ -4430,9 +4527,6 @@ static void json_detail_list(nvme_root_t t)
nvme_host_t h;
nvme_subsystem_t s;
- nvme_ctrl_t c;
- nvme_path_t p;
- nvme_ns_t n;
nvme_for_each_host(t, h) {
struct json_object *hss = json_create_object();
@@ -4446,76 +4540,14 @@ static void json_detail_list(nvme_root_t t)
nvme_for_each_subsystem(h, s) {
struct json_object *jss = json_create_object();
- struct json_object *jctrls = json_create_array();
- struct json_object *jnss = json_create_array();
obj_add_str(jss, "Subsystem", nvme_subsystem_get_name(s));
obj_add_str(jss, "SubsystemNQN", nvme_subsystem_get_nqn(s));
- nvme_subsystem_for_each_ctrl(s, c) {
- struct json_object *jctrl = json_create_object();
- struct json_object *jnss = json_create_array();
- struct json_object *jpaths = json_create_array();
-
- obj_add_str(jctrl, "Controller", nvme_ctrl_get_name(c));
- obj_add_str(jctrl, "Cntlid", nvme_ctrl_get_cntlid(c));
- obj_add_str(jctrl, "SerialNumber", nvme_ctrl_get_serial(c));
- obj_add_str(jctrl, "ModelNumber", nvme_ctrl_get_model(c));
- obj_add_str(jctrl, "Firmware", nvme_ctrl_get_firmware(c));
- obj_add_str(jctrl, "Transport", nvme_ctrl_get_transport(c));
- obj_add_str(jctrl, "Address", nvme_ctrl_get_address(c));
- obj_add_str(jctrl, "Slot", nvme_ctrl_get_phy_slot(c));
-
- nvme_ctrl_for_each_ns(c, n) {
- struct json_object *jns = json_create_object();
- int lba = nvme_ns_get_lba_size(n);
- uint64_t nsze = nvme_ns_get_lba_count(n) * lba;
- uint64_t nuse = nvme_ns_get_lba_util(n) * lba;
-
- obj_add_str(jns, "NameSpace", nvme_ns_get_name(n));
- obj_add_str(jns, "Generic", nvme_ns_get_generic_name(n));
- obj_add_int(jns, "NSID", nvme_ns_get_nsid(n));
- obj_add_uint64(jns, "UsedBytes", nuse);
- obj_add_uint64(jns, "MaximumLBA", nvme_ns_get_lba_count(n));
- obj_add_uint64(jns, "PhysicalSize", nsze);
- obj_add_int(jns, "SectorSize", lba);
-
- array_add_obj(jnss, jns);
- }
- obj_add_obj(jctrl, "Namespaces", jnss);
-
- nvme_ctrl_for_each_path(c, p) {
- struct json_object *jpath = json_create_object();
-
- obj_add_str(jpath, "Path", nvme_path_get_name(p));
- obj_add_str(jpath, "ANAState", nvme_path_get_ana_state(p));
-
- array_add_obj(jpaths, jpath);
- }
- obj_add_obj(jctrl, "Paths", jpaths);
-
- array_add_obj(jctrls, jctrl);
- }
- obj_add_obj(jss, "Controllers", jctrls);
-
- nvme_subsystem_for_each_ns(s, n) {
- struct json_object *jns = json_create_object();
-
- int lba = nvme_ns_get_lba_size(n);
- uint64_t nsze = nvme_ns_get_lba_count(n) * lba;
- uint64_t nuse = nvme_ns_get_lba_util(n) * lba;
-
- obj_add_str(jns, "NameSpace", nvme_ns_get_name(n));
- obj_add_str(jns, "Generic", nvme_ns_get_generic_name(n));
- obj_add_int(jns, "NSID", nvme_ns_get_nsid(n));
- obj_add_uint64(jns, "UsedBytes", nuse);
- obj_add_uint64(jns, "MaximumLBA", nvme_ns_get_lba_count(n));
- obj_add_uint64(jns, "PhysicalSize", nsze);
- obj_add_int(jns, "SectorSize", lba);
-
- array_add_obj(jnss, jns);
- }
- obj_add_obj(jss, "Namespaces", jnss);
+ if (nvme_is_multipath(s))
+ json_print_detail_list_multipath(s, jss);
+ else
+ json_print_detail_list(s, jss);
array_add_obj(jsslist, jss);
}
diff --git a/nvme-print-stdout.c b/nvme-print-stdout.c
index 7943b91c..52d8d2b1 100644
--- a/nvme-print-stdout.c
+++ b/nvme-print-stdout.c
@@ -5589,18 +5589,6 @@ static void stdout_list_items(nvme_root_t r)
stdout_simple_list(r);
}
-static bool nvme_is_multipath(nvme_subsystem_t s)
-{
- nvme_ns_t n;
- nvme_path_t p;
-
- nvme_subsystem_for_each_ns(s, n)
- nvme_namespace_for_each_path(n, p)
- return true;
-
- return false;
-}
-
static void stdout_subsystem_topology_multipath(nvme_subsystem_t s,
enum nvme_cli_topo_ranking ranking)
{
diff --git a/nvme.h b/nvme.h
index 1a15fc18..248c5c7c 100644
--- a/nvme.h
+++ b/nvme.h
@@ -122,6 +122,18 @@ static inline nvme_mi_ep_t dev_mi_ep(struct nvme_dev *dev)
return dev->mi.ep;
}
+static inline bool nvme_is_multipath(nvme_subsystem_t s)
+{
+ nvme_ns_t n;
+ nvme_path_t p;
+
+ nvme_subsystem_for_each_ns(s, n)
+ nvme_namespace_for_each_path(n, p)
+ return true;
+
+ return false;
+}
+
void register_extension(struct plugin *plugin);
/*
--
2.50.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] nvme-list: fix verbose JSON output for 'nvme list' command
2025-07-21 10:29 [PATCH] nvme-list: fix verbose JSON output for 'nvme list' command Nilay Shroff
@ 2025-07-24 14:18 ` Daniel Wagner
2025-08-04 15:25 ` Daniel Wagner
0 siblings, 1 reply; 6+ messages in thread
From: Daniel Wagner @ 2025-07-24 14:18 UTC (permalink / raw)
To: linux-nvme, Nilay Shroff; +Cc: Daniel Wagner, dwagner, msmurthy, gjoyce
On Mon, 21 Jul 2025 15:59:11 +0530, Nilay Shroff wrote:
> The verbose JSON output of the nvme list command is currently incorrect in
> both multipath and non-multipath configurations. Specifically, it prints
> empty Namespaces[] and Paths[] arrays in the wrong places, leading to
> confusion and invalid output. For example, on a system with single NVMe
> disk, signle controller and one namepsace created, 'nvme list --verbose
> --output json' prints the following output:
>
> [...]
Applied, thanks!
[1/1] nvme-list: fix verbose JSON output for 'nvme list' command
commit: 64bed0a87a23ca574cfce64fbcf6630194551276
Best regards,
--
Daniel Wagner <wagi@kernel.org>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] nvme-list: fix verbose JSON output for 'nvme list' command
2025-07-24 14:18 ` Daniel Wagner
@ 2025-08-04 15:25 ` Daniel Wagner
2025-08-05 4:30 ` Nilay Shroff
0 siblings, 1 reply; 6+ messages in thread
From: Daniel Wagner @ 2025-08-04 15:25 UTC (permalink / raw)
To: Nilay Shroff; +Cc: linux-nvme, msmurthy, gjoyce
On Thu, Jul 24, 2025 at 04:18:16PM +0200, Daniel Wagner wrote:
>
> On Mon, 21 Jul 2025 15:59:11 +0530, Nilay Shroff wrote:
> > The verbose JSON output of the nvme list command is currently incorrect in
> > both multipath and non-multipath configurations. Specifically, it prints
> > empty Namespaces[] and Paths[] arrays in the wrong places, leading to
> > confusion and invalid output. For example, on a system with single NVMe
> > disk, signle controller and one namepsace created, 'nvme list --verbose
> > --output json' prints the following output:
> >
> > [...]
FYI, this patch is causing a regression:
https://github.com/linux-nvme/nvme-cli/issues/2886
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] nvme-list: fix verbose JSON output for 'nvme list' command
2025-08-04 15:25 ` Daniel Wagner
@ 2025-08-05 4:30 ` Nilay Shroff
2025-08-05 7:27 ` Daniel Wagner
0 siblings, 1 reply; 6+ messages in thread
From: Nilay Shroff @ 2025-08-05 4:30 UTC (permalink / raw)
To: Daniel Wagner; +Cc: linux-nvme, msmurthy, gjoyce
On 8/4/25 8:55 PM, Daniel Wagner wrote:
> On Thu, Jul 24, 2025 at 04:18:16PM +0200, Daniel Wagner wrote:
>>
>> On Mon, 21 Jul 2025 15:59:11 +0530, Nilay Shroff wrote:
>>> The verbose JSON output of the nvme list command is currently incorrect in
>>> both multipath and non-multipath configurations. Specifically, it prints
>>> empty Namespaces[] and Paths[] arrays in the wrong places, leading to
>>> confusion and invalid output. For example, on a system with single NVMe
>>> disk, signle controller and one namepsace created, 'nvme list --verbose
>>> --output json' prints the following output:
>>>
>>> [...]
>
> FYI, this patch is causing a regression:
>
> https://github.com/linux-nvme/nvme-cli/issues/2886
Okay so does it make sense to retain the old output with the
default --output-format-version=1? But then if the user selects
--output-format-version=2 then we'd switch to the new output
format?
Thanks,
--Nilay
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] nvme-list: fix verbose JSON output for 'nvme list' command
2025-08-05 4:30 ` Nilay Shroff
@ 2025-08-05 7:27 ` Daniel Wagner
2025-08-05 10:18 ` Nilay Shroff
0 siblings, 1 reply; 6+ messages in thread
From: Daniel Wagner @ 2025-08-05 7:27 UTC (permalink / raw)
To: Nilay Shroff; +Cc: linux-nvme, msmurthy, gjoyce, tbzatek
On Tue, Aug 05, 2025 at 10:00:53AM +0530, Nilay Shroff wrote:
> > https://github.com/linux-nvme/nvme-cli/issues/2886
>
> Okay so does it make sense to retain the old output with the
> default --output-format-version=1? But then if the user selects
> --output-format-version=2 then we'd switch to the new output
> format?
Yes, the default output for nvme-cli v2 should be
--output-format-version=1. As suggested by Tomáš we can set default
format version to 2, for the next major nvme-cli release.
Thanks,
Daniel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] nvme-list: fix verbose JSON output for 'nvme list' command
2025-08-05 7:27 ` Daniel Wagner
@ 2025-08-05 10:18 ` Nilay Shroff
0 siblings, 0 replies; 6+ messages in thread
From: Nilay Shroff @ 2025-08-05 10:18 UTC (permalink / raw)
To: Daniel Wagner; +Cc: linux-nvme, msmurthy, gjoyce, tbzatek
On 8/5/25 12:57 PM, Daniel Wagner wrote:
> On Tue, Aug 05, 2025 at 10:00:53AM +0530, Nilay Shroff wrote:
>>> https://github.com/linux-nvme/nvme-cli/issues/2886
>>
>> Okay so does it make sense to retain the old output with the
>> default --output-format-version=1? But then if the user selects
>> --output-format-version=2 then we'd switch to the new output
>> format?
>
> Yes, the default output for nvme-cli v2 should be
> --output-format-version=1. As suggested by Tomáš we can set default
> format version to 2, for the next major nvme-cli release.
>
Okay so I have made changes for ensuring backward compatibility.
The changes are on its way...
Thanks,
--Nilay
^ permalink raw reply [flat|nested] 6+ messages in thread
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