[PATCH] python: Support resource clearing

[Nir Soffer]

From: Nir Soffer <nsoffer(a)redhat.com&gt;

Add the missing flags kwarg to sanlock.write_resource(), and the new
sanlock.WRITE_CLEAR constant.

To clear a resource, you can do now:

    sanlock.write_resource("lockspace", "resource",
[("/path/to/resource", 0)],
                           flags=sanlock.WRITE_CLEAR)

Subsequent sanlock.read_resource() calls will return the regular error
when a resource is not found.

Signed-off-by: Nir Soffer <nsoffer(a)redhat.com&gt;
---
 python/sanlock.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/python/sanlock.c b/python/sanlock.c
index 40da92f..af89d17 100644
--- a/python/sanlock.c
+++ b/python/sanlock.c
@@ -551,25 +551,28 @@ exit_fail:
 
 /* write_resource */
 PyDoc_STRVAR(pydoc_write_resource, "\
-write_resource(lockspace, resource, disks, max_hosts=0, num_hosts=0)\n\
+write_resource(lockspace, resource, disks, max_hosts=0, num_hosts=0, flags=0)\n\
 Initialize a device to be used as sanlock resource.\n\
-The disks must be in the format: [(path, offset), ... ]");
+The disks must be in the format: [(path, offset), ... ].\n\
+If WRITE_CLEAR flag is used, the resource is cleared so subsequent read will\n\
+return an error.");
 
 static PyObject *
 py_write_resource(PyObject *self __unused, PyObject *args, PyObject *keywds)
 {
     int rv, max_hosts = 0, num_hosts = 0;
+    uint32_t flags = 0;
     const char *lockspace, *resource;
     struct sanlk_resource *rs;
     PyObject *disks;
 
     static char *kwlist[] = {"lockspace", "resource",
"disks", "max_hosts",
-                                "num_hosts", NULL};
+                                "num_hosts", "flags", NULL};
 
     /* parse python tuple */
-    if (!PyArg_ParseTupleAndKeywords(args, keywds, "ssO!|ii",
+    if (!PyArg_ParseTupleAndKeywords(args, keywds, "ssO!|iiI",
         kwlist, &lockspace, &resource, &PyList_Type, &disks,
&max_hosts,
-        &num_hosts)) {
+        &num_hosts, &flags)) {
         return NULL;
     }
 
@@ -584,7 +587,7 @@ py_write_resource(PyObject *self __unused, PyObject *args, PyObject
*keywds)
 
     /* init sanlock resource (gil disabled) */
     Py_BEGIN_ALLOW_THREADS
-    rv = sanlock_write_resource(rs, max_hosts, num_hosts, 0);
+    rv = sanlock_write_resource(rs, max_hosts, num_hosts, flags);
     Py_END_ALLOW_THREADS
 
     if (rv != 0) {
@@ -1605,6 +1608,9 @@ initsanlock(void)
     PYSNLK_INIT_ADD_CONSTANT(SANLK_REQ_FORCE, "REQ_FORCE");
     PYSNLK_INIT_ADD_CONSTANT(SANLK_REQ_GRACEFUL, "REQ_GRACEFUL");
 
+    /* resource write flags */
+    PYSNLK_INIT_ADD_CONSTANT(SANLK_WRITE_CLEAR, "WRITE_CLEAR");
+
     /* hosts list flags */
     PYSNLK_INIT_ADD_CONSTANT(SANLK_HOST_FREE, "HOST_FREE");
     PYSNLK_INIT_ADD_CONSTANT(SANLK_HOST_LIVE, "HOST_LIVE");
-- 
2.7.4

[Nir Soffer]

On Sat, Dec 3, 2016 at 10:44 PM, Nir Soffer <nirsof(a)gmail.com&gt; wrote:
>  From: Nir Soffer <nsoffer(a)redhat.com&gt;
>
>  Add the missing flags kwarg to sanlock.write_resource(), and the new
>  sanlock.WRITE_CLEAR constant.
>
>  To clear a resource, you can do now:
>
>      sanlock.write_resource("lockspace", "resource",
> [("/path/to/resource", 0)],
>                             flags=sanlock.WRITE_CLEAR) 
Looking again in other calls, the python binding is typically hiding the
underlying flags argument with a python kwarg.

for example:

    sanlock.rem_lockspace("lockspace", 1, "/path/to/lockspace",
async=True)

So I think we should continue this style and have:

    sanlock.write_resource("lockspace", "resource",
[("/path/to/resource", 0)], clear=True)

This is more pythonic, self documenting and we don't need to expose
the constant.

I'll send a better patch later.

>
> Subsequent sanlock.read_resource() calls will return the regular error
> when a resource is not found.
>
> Signed-off-by: Nir Soffer <nsoffer(a)redhat.com&gt;
> ---
>  python/sanlock.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/python/sanlock.c b/python/sanlock.c
> index 40da92f..af89d17 100644
> --- a/python/sanlock.c
> +++ b/python/sanlock.c
> @@ -551,25 +551,28 @@ exit_fail:
>
>  /* write_resource */
>  PyDoc_STRVAR(pydoc_write_resource, "\
> -write_resource(lockspace, resource, disks, max_hosts=0, num_hosts=0)\n\
> +write_resource(lockspace, resource, disks, max_hosts=0, num_hosts=0, flags=0)\n\
>  Initialize a device to be used as sanlock resource.\n\
> -The disks must be in the format: [(path, offset), ... ]");
> +The disks must be in the format: [(path, offset), ... ].\n\
> +If WRITE_CLEAR flag is used, the resource is cleared so subsequent read will\n\
> +return an error.");
>
>  static PyObject *
>  py_write_resource(PyObject *self __unused, PyObject *args, PyObject *keywds)
>  {
>      int rv, max_hosts = 0, num_hosts = 0;
> +    uint32_t flags = 0;
>      const char *lockspace, *resource;
>      struct sanlk_resource *rs;
>      PyObject *disks;
>
>      static char *kwlist[] = {"lockspace", "resource",
"disks", "max_hosts",
> -                                "num_hosts", NULL};
> +                                "num_hosts", "flags", NULL};
>
>      /* parse python tuple */
> -    if (!PyArg_ParseTupleAndKeywords(args, keywds, "ssO!|ii",
> +    if (!PyArg_ParseTupleAndKeywords(args, keywds, "ssO!|iiI",
>          kwlist, &lockspace, &resource, &PyList_Type, &disks,
&max_hosts,
> -        &num_hosts)) {
> +        &num_hosts, &flags)) {
>          return NULL;
>      }
>
> @@ -584,7 +587,7 @@ py_write_resource(PyObject *self __unused, PyObject *args,
PyObject *keywds)
>
>      /* init sanlock resource (gil disabled) */
>      Py_BEGIN_ALLOW_THREADS
> -    rv = sanlock_write_resource(rs, max_hosts, num_hosts, 0);
> +    rv = sanlock_write_resource(rs, max_hosts, num_hosts, flags);
>      Py_END_ALLOW_THREADS
>
>      if (rv != 0) {
> @@ -1605,6 +1608,9 @@ initsanlock(void)
>      PYSNLK_INIT_ADD_CONSTANT(SANLK_REQ_FORCE, "REQ_FORCE");
>      PYSNLK_INIT_ADD_CONSTANT(SANLK_REQ_GRACEFUL, "REQ_GRACEFUL");
>
> +    /* resource write flags */
> +    PYSNLK_INIT_ADD_CONSTANT(SANLK_WRITE_CLEAR, "WRITE_CLEAR");
> +
>      /* hosts list flags */
>      PYSNLK_INIT_ADD_CONSTANT(SANLK_HOST_FREE, "HOST_FREE");
>      PYSNLK_INIT_ADD_CONSTANT(SANLK_HOST_LIVE, "HOST_LIVE");
> --
> 2.7.4
>

[PATCH v2] python: Support resource clearing

[Nir Soffer]

From: Nir Soffer <nsoffer(a)redhat.com&gt;

Add a clear kwarg to sanlock.write_resource(), using SANLK_WRITE_CLEAR
to clear the resource.

To clear a resource, you can do now:

    sanlock.write_resource("lockspace", "resource",
[("/path/to/resource", 0)],
                           clear=True)

Subsequent sanlock.read_resource() calls will return the regular error
when a resource is not found.

Signed-off-by: Nir Soffer <nsoffer(a)redhat.com&gt;
---
 python/sanlock.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/python/sanlock.c b/python/sanlock.c
index 40da92f..f2ad672 100644
--- a/python/sanlock.c
+++ b/python/sanlock.c
@@ -551,25 +551,29 @@ exit_fail:
 
 /* write_resource */
 PyDoc_STRVAR(pydoc_write_resource, "\
-write_resource(lockspace, resource, disks, max_hosts=0, num_hosts=0)\n\
+write_resource(lockspace, resource, disks, max_hosts=0, num_hosts=0, \
+clear=False)\n\
 Initialize a device to be used as sanlock resource.\n\
-The disks must be in the format: [(path, offset), ... ]");
+The disks must be in the format: [(path, offset), ... ].\n\
+If clear is True, the resource is cleared so subsequent read will\n\
+return an error.");
 
 static PyObject *
 py_write_resource(PyObject *self __unused, PyObject *args, PyObject *keywds)
 {
-    int rv, max_hosts = 0, num_hosts = 0;
+    int rv, max_hosts = 0, num_hosts = 0, clear = 0;
     const char *lockspace, *resource;
     struct sanlk_resource *rs;
     PyObject *disks;
+    uint32_t flags = 0;
 
     static char *kwlist[] = {"lockspace", "resource",
"disks", "max_hosts",
-                                "num_hosts", NULL};
+                                "num_hosts", "clear", NULL};
 
     /* parse python tuple */
-    if (!PyArg_ParseTupleAndKeywords(args, keywds, "ssO!|ii",
+    if (!PyArg_ParseTupleAndKeywords(args, keywds, "ssO!|iii",
         kwlist, &lockspace, &resource, &PyList_Type, &disks,
&max_hosts,
-        &num_hosts)) {
+        &num_hosts, &clear)) {
         return NULL;
     }
 
@@ -582,9 +586,13 @@ py_write_resource(PyObject *self __unused, PyObject *args, PyObject
*keywds)
     strncpy(rs->lockspace_name, lockspace, SANLK_NAME_LEN);
     strncpy(rs->name, resource, SANLK_NAME_LEN);
 
+    if (clear) {
+        flags |= SANLK_WRITE_CLEAR;
+    }
+
     /* init sanlock resource (gil disabled) */
     Py_BEGIN_ALLOW_THREADS
-    rv = sanlock_write_resource(rs, max_hosts, num_hosts, 0);
+    rv = sanlock_write_resource(rs, max_hosts, num_hosts, flags);
     Py_END_ALLOW_THREADS
 
     if (rv != 0) {
-- 
2.7.4