Details
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Bug
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Resolution: Fixed
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Minor
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Lustre 2.3.0
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None
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lustre 2.2.93
bullxlinux distribution (based on redhat 6.2)
kernel 2.6.32-220
Description
Unmount of lustre target fails when target device is a multipath device.
# mount -t lustre /dev/dm-47 /mnt/fsperf/ost/0 # cat /etc/mtab /dev/dm-47 /mnt/fsperf/ost/0 lustre rw 0 0 # cat /sys/block/dm-47/dm/name mpathau # ls -l /dev/mapper/mpathau lrwxrwxrwx 1 root root 8 Sep 7 09:54 /dev/mapper/mpathau -> ../dm-47 # umount /dev/dm-47 umount: /dev/dm-47: not mounted # umount -v /dev/dm-47 Could not find /dev/mapper/mpathau in mtab # umount -v /dev/mapper/mpathau Could not find /dev/mapper/mpathau in mtab umount: /dev/mapper/mpathau: not mounted
This is because mount.lustre and umount commands do not handle multipath devices the same way.
'mount.lustre /dev/dm-47' inserts an entry in /etc/mtab with device named: /dev/dm-47
'umount /dev/dm-47' looks for an entry in /etc/mtab named: /dev/mapper/mpathau.
In previous lustre version, the mount.lustre command was insterting in /etc/mtab the '/dev/mapper/mpathau' device name. This changed with commit 2d7e03100adb7975601a194e476bee50d8e2413c for LU-1581 because computation of '/dev/mapper/mpathxx' name has no effect on mo_usource field since the string was duplicated from real_path: 'strdup(real_path)'.
/**
* Try to get the real path to the device, in case it is a
* symbolic link for instance
*/
if (realpath(mop->mo_usource, real_path) != NULL) {
mop->mo_usource = strdup(real_path);
ptr = strrchr(real_path, '/');
if (ptr && strncmp(ptr, "/dm-", 4) == 0 && isdigit(*(ptr + 4))) {
snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptr+1);
if ((f = fopen(path, "r"))) {
/* read "<name>\n" from sysfs */
if (fgets(name, sizeof(name), f) && (sz = strlen(name)) > 1) {
name[sz - 1] = '\0';
snprintf(real_path, sizeof(real_path), "/dev/mapper/%s", name);
}
fclose(f);
}
}
}
I will provide a patch.