block monitor: freeze spare assignment for external arrays

[thirdparty/mdadm.git] / sysfs.c

diff --git a/sysfs.c b/sysfs.c
index 6e1d77b313daf28189cfa38e753c022f92bdfd71..16e41fbefbd8b97653862e5e49b8905563e98b47 100644 (file)
--- a/sysfs.c
+++ b/sysfs.c
@@ -435,6 +435,17 @@ int sysfs_uevent(struct mdinfo *sra, char *event)
        return 0;
 }      
 
+int sysfs_attribute_available(struct mdinfo *sra, struct mdinfo *dev, char *name)
+{
+       char fname[50];
+       struct stat st;
+
+       sprintf(fname, "/sys/block/%s/md/%s/%s",
+               sra->sys_name, dev?dev->sys_name:"", name);
+
+       return stat(fname, &st) == 0;
+}
+
 int sysfs_get_fd(struct mdinfo *sra, struct mdinfo *dev,
                       char *name)
 {
@@ -789,6 +800,28 @@ int sysfs_unique_holder(int devnum, long rdev)
                return found;
 }
 
+int sysfs_freeze_array(struct mdinfo *sra)
+{
+       /* Try to freeze resync/rebuild on this array/container.
+        * Return -1 if the array is busy,
+        * return -2 container cannot be frozen,
+        * return 0 if this kernel doesn't support 'frozen'
+        * return 1 if it worked.
+        */
+       char buf[20];
+
+       if (!sysfs_attribute_available(sra, NULL, "sync_action"))
+               return 1; /* no sync_action == frozen */
+       if (sysfs_get_str(sra, NULL, "sync_action", buf, 20) <= 0)
+               return 0;
+       if (strcmp(buf, "idle\n") != 0 &&
+           strcmp(buf, "frozen\n") != 0)
+               return -1;
+       if (sysfs_set_str(sra, NULL, "sync_action", "frozen") < 0)
+               return 0;
+       return 1;
+}
+
 #ifndef MDASSEMBLE
 
 static char *clean_states[] = {