Add new mode: --incremental

[thirdparty/mdadm.git] / mdopen.c

diff --git a/mdopen.c b/mdopen.c
index 9f3dfb8465ec31a10b72e8816ea7c93ef7b81321..0b6951d2d4dfc4a2bd7b9a67c54d8b7d83463e2a 100644 (file)
--- a/mdopen.c
+++ b/mdopen.c
@@ -292,3 +292,51 @@ int open_mddev(char *dev, int autof)
        return mdfd;
 }
 
+
+int open_mddev_devnum(char *devname, int devnum, char *name, char *chosen_name)
+{
+       /* Open the md device with number 'devnum', possibly using 'devname',
+        * possibly constructing a name with 'name', but in any case, copying
+        * the name into 'chosen_name'
+        */
+       int major, minor;
+       struct stat stb;
+
+       if (devname)
+               strcpy(chosen_name, devname);
+       else if (name && strchr(name,'/') == NULL) {
+               char *n = strchr(name, ':');
+               if (n) n++; else n = name;
+               if (isdigit(*n) && devnum < 0)
+                       sprintf(chosen_name, "/dev/md/d%s", n);
+               else
+                       sprintf(chosen_name, "/dev/md/%s", n);
+       } else {
+               if (devnum >= 0)
+                       sprintf(chosen_name, "/dev/md%d", devnum);
+               else
+                       sprintf(chosen_name, "/dev/md/d%d", -1-devnum);
+       }
+       if (devnum >= 0) {
+               major = MD_MAJOR;
+               minor = devnum;
+       } else {
+               major = get_mdp_major();
+               minor = (-1-devnum) << 6;
+       }
+       if (stat(chosen_name, &stb) == 0) {
+               /* It already exists.  Check it is right. */
+               if ( ! S_ISBLK(stb.st_mode) ||
+                    stb.st_rdev != makedev(major, minor)) {
+                       errno = EEXIST;
+                       return -1;
+               }
+       } else {
+               if (mknod(chosen_name, S_IFBLK | 0600,
+                         makedev(major, minor)) != 0) {
+                       return -1;
+               }
+               /* FIXME chown/chmod ?? */
+       }
+       return open(chosen_name, O_RDWR);
+}