File 0008-Retry-HOT_REMOVE_DISK-a-few-times.patch of Package mdadm

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File 0008-Retry-HOT_REMOVE_DISK-a-few-times.patch of Package mdadm (Revision 8b11ac56120fbccfb57db53735de41d8)

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From 3494e6b41659393c7cb97c48b45d2b1a05c6faf0 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.com>
Date: Mon, 27 Mar 2017 12:48:06 +1100
Subject: [PATCH] Retry HOT_REMOVE_DISK a few times.

HOT_REMOVE_DISK can fail with EBUSY if there are outstanding
IO request that have not completed yet.  It can sometimes
be helpful to wait a little while for these to complete.

We already do this in impose_level() when reshaping a device,
but not in Manage.c in response to an explicit --remove request.

So create hot_remove_disk() to central this code, and call it
where-ever it makes sense to wait for a HOT_REMOVE_DISK to succeed.

Signed-off-by: NeilBrown <neilb@suse.com>
---
 Grow.c   |    9 +--------
 Manage.c |    4 ++--
 mdadm.h  |    1 +
 util.c   |   18 ++++++++++++++++++
 4 files changed, 22 insertions(+), 10 deletions(-)

--- a/Grow.c
+++ b/Grow.c
@@ -2921,7 +2921,6 @@ static int impose_level(int fd, int leve
 		for (d = 0, found = 0;
 		     d < MAX_DISKS && found < array.nr_disks;
 		     d++) {
-			int cnt;
 			mdu_disk_info_t disk;
 			disk.number = d;
 			if (ioctl(fd, GET_DISK_INFO, &disk) < 0)
@@ -2935,13 +2934,7 @@ static int impose_level(int fd, int leve
 				continue;
 			ioctl(fd, SET_DISK_FAULTY,
 			      makedev(disk.major, disk.minor));
-			cnt = 5;
-			while (ioctl(fd, HOT_REMOVE_DISK,
-				     makedev(disk.major, disk.minor)) < 0
-			       && errno == EBUSY
-			       && cnt--) {
-				usleep(10000);
-			}
+			hot_remove_disk(fd, makedev(disk.major, disk.minor));
 		}
 	}
 	c = map_num(pers, level);
--- a/Manage.c
+++ b/Manage.c
@@ -1183,7 +1183,7 @@ int Manage_remove(struct supertype *tst,
 		else
 			err = 0;
 	} else {
-		err = ioctl(fd, HOT_REMOVE_DISK, rdev);
+		err = hot_remove_disk(fd, rdev);
 		if (err && errno == ENODEV) {
 			/* Old kernels rejected this if no personality
 			 * is registered */
@@ -1607,7 +1607,7 @@ int Manage_subdevs(char *devname, int fd
 
 			if (dv->disposition == 'F')
 				/* Need to remove first */
-				ioctl(fd, HOT_REMOVE_DISK, rdev);
+				hot_remove_disk(fd, rdev);
 			/* Make sure it isn't in use (in 2.6 or later) */
 			tfd = dev_open(dv->devname, O_RDONLY|O_EXCL);
 			if (tfd >= 0) {
--- a/mdadm.h
+++ b/mdadm.h
@@ -1500,6 +1500,7 @@ extern int add_disk(int mdfd, struct sup
 		    struct mdinfo *sra, struct mdinfo *info);
 extern int remove_disk(int mdfd, struct supertype *st,
 		       struct mdinfo *sra, struct mdinfo *info);
+extern int hot_remove_disk(int mdfd, unsigned long dev);
 extern int set_array_info(int mdfd, struct supertype *st, struct mdinfo *info);
 unsigned long long min_recovery_start(struct mdinfo *array);
 
--- a/util.c
+++ b/util.c
@@ -1795,6 +1795,24 @@ int remove_disk(int mdfd, struct superty
 	return rv;
 }
 
+int hot_remove_disk(int mdfd, unsigned long dev)
+{
+	int cnt = 5;
+	int ret;
+
+	/* HOT_REMOVE_DISK can fail with EBUSY if there are
+	 * outstanding IO requests to the device.
+	 * In this case, it can be helpful to wait a little while,
+	 * up to half a second, for that IO to flush.
+	 */
+	while ((ret = ioctl(mdfd, HOT_REMOVE_DISK, dev)) == -1 &&
+	       errno == EBUSY &&
+	       cnt-- > 0)
+		usleep(10000);
+
+	return ret;
+}
+
 int set_array_info(int mdfd, struct supertype *st, struct mdinfo *info)
 {
 	/* Initialise kernel's knowledge of array.

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