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Remove: container should wait for an array to release a drive 

A 'faulty' drive is being removed from a container after it has been
released by an array, however there is a race there. The drive is
released asynchronously by a monitor but sometimes it doesn't happen
before container checks it. It results in a container refusing to remove
a drive as it still seems to be a part of some array.

It seems 'ping_monitor' could be a solution here to assure monitor has
had a chance to process the events, however it doesn't resolve the
problem - sometimes an array has to request a release of the drive few
times (as the array is busy) and single 'ping_monitor' call is not
sufficient. As there is no way to query monitor progress, it forces us
to retry a check several times before an error is returned.

Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
This commit is contained in:
Tomasz Majchrzak 2016-07-21 09:59:42 +02:00 committed by Jes Sorensen
parent 0febb20c45
commit c922221e25
1 changed files with 28 additions and 13 deletions
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41
Manage.c
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@ -1125,19 +1125,34 @@ int Manage_remove(struct supertype *tst, int fd, struct mddev_dev *dv,
*/
if (rdev == 0)
ret = -1;
else
ret = sysfs_unique_holder(devnm, rdev);
if (ret == 0) {
pr_err("%s is not a member, cannot remove.\n",
dv->devname);
close(lfd);
return -1;
}
if (ret >= 2) {
pr_err("%s is still in use, cannot remove.\n",
dv->devname);
close(lfd);
return -1;
else {
/*
* The drive has already been set to 'faulty', however
* monitor might not have had time to process it and the
* drive might still have an entry in the 'holders'
* directory. Try a few times to avoid a false error
*/
int count = 20;
do {
ret = sysfs_unique_holder(devnm, rdev);
if (ret < 2)
break;
usleep(100 * 1000); /* 100ms */
} while (--count > 0);
if (ret == 0) {
pr_err("%s is not a member, cannot remove.\n",
dv->devname);
close(lfd);
return -1;
}
if (ret >= 2) {
pr_err("%s is still in use, cannot remove.\n",
dv->devname);
close(lfd);
return -1;
}
}
}
/* FIXME check that it is a current member */