File 0001-Remove-container-should-wait-for-an-array-... of Package mdadm.3522

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File 0001-Remove-container-should-wait-for-an-array-to-release.patch of Package mdadm.3522

From c922221e2522fd24f86e5a0de0bfba60b14353c0 Mon Sep 17 00:00:00 2001
From: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
Date: Thu, 21 Jul 2016 09:59:42 +0200
Subject: [PATCH] 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>
---
 Manage.c |   41 ++++++++++++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 13 deletions(-)

--- a/Manage.c
+++ b/Manage.c
@@ -1139,19 +1139,34 @@ int Manage_remove(struct supertype *tst,
 		 */
 		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 */

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File 0001-Remove-container-should-wait-for-an-array-to-release.patch of Package mdadm.3522

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