[Devel] [PATCH RHEL COMMIT] ve/uts_ns: Implement cgroup interface to configure ve's os_release
Konstantin Khorenko
khorenko at virtuozzo.com
Fri Sep 24 15:48:49 MSK 2021
The commit is pushed to "branch-rh9-5.14.vz9.1.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after ark-5.14
------>
commit e4a4535af65d5afb7dc6bf2962be402f600ca374
Author: Kirill Tkhai <ktkhai at odin.com>
Date: Fri Sep 24 15:48:49 2021 +0300
ve/uts_ns: Implement cgroup interface to configure ve's os_release
It's the similar to VZCTL_VE_CONFIGURE ioctl in PCS6.
Note: max_write_len is __NEW_UTS_LEN + 1, because I want to allow
echo ... > ve.os_release, which adds trailing '\n' to the string
(see man echo for details).
Extra symbol will be cut in ve_os_release_write().
https://jira.sw.ru/browse/PSBM-32273
Signed-off-by: Kirill Tkhai <ktkhai at odin.com>
Signed-off-by: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
(cherry picked from vz8 commit d9c541f7a5f43f1f39df07f3b50d2704c3f2fe9b)
Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
---
kernel/ve/ve.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)
diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
index 560a63902127..75299258d677 100644
--- a/kernel/ve/ve.c
+++ b/kernel/ve/ve.c
@@ -718,6 +718,55 @@ static u64 ve_netns_avail_nr_read(struct cgroup_subsys_state *css, struct cftype
return atomic_read(&css_to_ve(css)->netns_avail_nr);
}
+static int ve_os_release_read(struct seq_file *sf, void *v)
+{
+ struct cgroup_subsys_state *css = seq_css(sf);
+ struct ve_struct *ve = css_to_ve(css);
+ int ret = 0;
+
+ down_read(&ve->op_sem);
+
+ if (!ve->ve_ns) {
+ ret = -ENOENT;
+ goto up_opsem;
+ }
+
+ down_read(&uts_sem);
+ seq_puts(sf, ve->ve_ns->uts_ns->name.release);
+ seq_putc(sf, '\n');
+ up_read(&uts_sem);
+up_opsem:
+ up_read(&ve->op_sem);
+
+ return ret;
+}
+
+static ssize_t ve_os_release_write(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off)
+{
+ struct cgroup_subsys_state *css = of_css(of);
+ struct ve_struct *ve = css_to_ve(css);
+ char *release;
+ int ret = 0;
+
+ down_read(&ve->op_sem);
+
+ if (!ve->ve_ns) {
+ ret = -ENOENT;
+ goto up_opsem;
+ }
+
+ down_write(&uts_sem);
+ release = ve->ve_ns->uts_ns->name.release;
+ strncpy(release, buf, __NEW_UTS_LEN);
+ release[__NEW_UTS_LEN] = '\0';
+ up_write(&uts_sem);
+up_opsem:
+ up_read(&ve->op_sem);
+
+ return ret ? ret : nbytes;
+}
+
static struct cftype ve_cftypes[] = {
{
@@ -754,6 +803,13 @@ static struct cftype ve_cftypes[] = {
.name = "netns_avail_nr",
.read_u64 = ve_netns_avail_nr_read,
},
+ {
+ .name = "os_release",
+ .max_write_len = __NEW_UTS_LEN + 1,
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = ve_os_release_read,
+ .write = ve_os_release_write,
+ },
{ }
};
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