From cb8f5371352f6c16af5aab8a40861e13aa50fc2b Mon Sep 17 00:00:00 2001
From: Mariusz Tkaczyk <mariusz.tkaczyk@intel.com>
Date: Fri, 3 Aug 2018 09:41:50 +0200
Subject: [PATCH] Incremental: remove external arrays and devices correctly

Kernel returns EBUSY when device fail invokes array fail.
In external metadata if kernel returns it, mdadm doesn't stop member
arrays but it will try to stop container directly. It fails because
container still has working arrays, so udev remove is triggered.

Try to set faulty state on device in member arrays first. If kernel
returns EBUSY, stop this array. After that remove the device from
container.

In external metadata mdmon has to remove faulty devices from degraded
arrays, just remove device from container.

Raid5 array doesn't return EBUSY, it allows to remove every device.
Mdadm shouldn't block it.

Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>
---
 Incremental.c | 78 ++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 52 insertions(+), 26 deletions(-)

diff --git a/Incremental.c b/Incremental.c
index 0c5698ee..a4ff7d4b 100644
--- a/Incremental.c
+++ b/Incremental.c
@@ -1683,6 +1683,44 @@ static void run_udisks(char *arg1, char *arg2)
 		;
 }
 
+static int force_remove(char *devnm, int fd, struct mdinfo *mdi, int verbose)
+{
+	int rv;
+	int devid = devnm2devid(devnm);
+
+	run_udisks("--unmount", map_dev(major(devid), minor(devid), 0));
+	rv = Manage_stop(devnm, fd, verbose, 1);
+	if (rv) {
+		/* At least we can try to trigger a 'remove' */
+		sysfs_uevent(mdi, "remove");
+		if (verbose)
+			pr_err("Fail to stop %s too.\n", devnm);
+	}
+	return rv;
+}
+
+static void remove_from_member_array(struct mdstat_ent *memb,
+				    struct mddev_dev *devlist, int verbose)
+{
+	int rv;
+	struct mdinfo mmdi;
+	int subfd = open_dev(memb->devnm);
+
+	if (subfd >= 0) {
+		rv = Manage_subdevs(memb->devnm, subfd, devlist, verbose,
+				    0, NULL, 0);
+		if (rv & 2) {
+			if (sysfs_init(&mmdi, -1, memb->devnm))
+				pr_err("unable to initialize sysfs for: %s\n",
+				       memb->devnm);
+			else
+				force_remove(memb->devnm, subfd, &mmdi,
+					     verbose);
+		}
+		close(subfd);
+	}
+}
+
 /*
  * IncrementalRemove - Attempt to see if the passed in device belongs to any
  * raid arrays, and if so first fail (if needed) and then remove the device.
@@ -1754,40 +1792,28 @@ int IncrementalRemove(char *devname, char *id_path, int verbose)
 	    strncmp(ent->metadata_version, "external:", 9) == 0) {
 		struct mdstat_ent *mdstat = mdstat_read(0, 0);
 		struct mdstat_ent *memb;
-		for (memb = mdstat ; memb ; memb = memb->next)
-			if (is_container_member(memb, ent->devnm)) {
-				int subfd = open_dev(memb->devnm);
-				if (subfd >= 0) {
-					rv |= Manage_subdevs(
-						memb->devnm, subfd,
-						&devlist, verbose, 0,
-						NULL, 0);
-					close(subfd);
-				}
-			}
+		for (memb = mdstat ; memb ; memb = memb->next) {
+			if (is_container_member(memb, ent->devnm))
+				remove_from_member_array(memb,
+					&devlist, verbose);
+		}
 		free_mdstat(mdstat);
-	} else
+	} else {
 		rv |= Manage_subdevs(ent->devnm, mdfd, &devlist,
 				    verbose, 0, NULL, 0);
-	if (rv & 2) {
+		if (rv & 2) {
 		/* Failed due to EBUSY, try to stop the array.
 		 * Give udisks a chance to unmount it first.
 		 */
-		int devid = devnm2devid(ent->devnm);
-		run_udisks("--unmount", map_dev(major(devid),minor(devid), 0));
-		rv = Manage_stop(ent->devnm, mdfd, verbose, 1);
-		if (rv)
-			/* At least we can try to trigger a 'remove' */
-			sysfs_uevent(&mdi, "remove");
-		if (verbose) {
-			if (rv)
-				pr_err("Fail to stop %s too.\n", ent->devnm);
+			rv = force_remove(ent->devnm, mdfd, &mdi, verbose);
+			goto end;
 		}
-	} else {
-		devlist.disposition = 'r';
-		rv = Manage_subdevs(ent->devnm, mdfd, &devlist,
-				    verbose, 0, NULL, 0);
 	}
+
+	devlist.disposition = 'r';
+	rv = Manage_subdevs(ent->devnm, mdfd, &devlist,
+			    verbose, 0, NULL, 0);
+end:
 	close(mdfd);
 	free_mdstat(ent);
 	return rv;
-- 
2.39.2