int stat2devnum(struct stat *st)
{
char path[30];
char link[200];
char *cp;
int n;
if ((S_IFMT & st->st_mode) == S_IFBLK) {
if (major(st->st_rdev) == MD_MAJOR)
return minor(st->st_rdev);
else if (major(st->st_rdev) == (unsigned)get_mdp_major())
return -1- (minor(st->st_rdev)>>MdpMinorShift);
/* must be an extended-minor partition. Look at the
* /sys/dev/block/%d:%d link which must look like
* ../../block/mdXXX/mdXXXpYY
*/
sprintf(path, "/sys/dev/block/%d:%d", major(st->st_rdev),
minor(st->st_rdev));
n = readlink(path, link, sizeof(link)-1);
if (n <= 0)
return NoMdDev;
link[n] = 0;
cp = strrchr(link, '/');
if (cp) *cp = 0;
cp = strrchr(link, '/');
if (cp && strncmp(cp, "/md", 3) == 0)
return devname2devnum(cp+1);
}
return NoMdDev;
}
unsigned long long get_component_size(int fd)
{
/* Find out the component size of the array.
* We cannot trust GET_ARRAY_INFO ioctl as it's
* size field is only 32bits.
* So look in /sys/block/mdXXX/md/component_size
*
* This returns in units of sectors.
*/
struct stat stb;
char fname[MAX_SYSFS_PATH_LEN];
int n;
if (fstat(fd, &stb))
return 0;
if (major(stb.st_rdev) != (unsigned)get_mdp_major())
snprintf(fname, MAX_SYSFS_PATH_LEN,
"/sys/block/md%d/md/component_size",
(int)minor(stb.st_rdev));
else
snprintf(fname, MAX_SYSFS_PATH_LEN,
"/sys/block/md_d%d/md/component_size",
(int)minor(stb.st_rdev)>>MdpMinorShift);
fd = open(fname, O_RDONLY);
if (fd < 0)
return 0;
n = read(fd, fname, sizeof(fname));
close(fd);
if (n < 0 || n == sizeof(fname))
return 0;
fname[n] = 0;
return strtoull(fname, NULL, 10) * 2;
}