From 2dd271fe7041c2f7036939cf6917c0578b92fefe Mon Sep 17 00:00:00 2001

From: NeilBrown <neilb@suse.com>

Date: Mon, 27 Mar 2017 12:50:16 +1100

Subject: [RHEL7.5 PATCH 020/169] 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>

Signed-off-by: Jes Sorensen <Jes.Sorensen@gmail.com>

---

 Grow.c   |  9 +--------

 Manage.c |  4 ++--

 mdadm.h  |  1 +

 util.c   | 18 ++++++++++++++++++

 4 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/Grow.c b/Grow.c

index 455c5f9..218a706 100755

--- a/Grow.c

+++ b/Grow.c

@@ -2736,7 +2736,6 @@ static int impose_level(int fd, int level, char *devname, int verbose)

 		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)

@@ -2750,13 +2749,7 @@ static int impose_level(int fd, int level, char *devname, int verbose)

 				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);

diff --git a/Manage.c b/Manage.c

index 5c3d2b9..9139f96 100644

--- a/Manage.c

+++ b/Manage.c

@@ -1183,7 +1183,7 @@ int Manage_remove(struct supertype *tst, int fd, struct mddev_dev *dv,

 		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) {

diff --git a/mdadm.h b/mdadm.h

index 91fd9eb..5bcfb86 100644

--- a/mdadm.h

+++ b/mdadm.h

@@ -1476,6 +1476,7 @@ extern int add_disk(int mdfd, struct supertype *st,

 		    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);

diff --git a/util.c b/util.c

index 32bd909..d09a7e2 100644

--- a/util.c

+++ b/util.c

@@ -1795,6 +1795,24 @@ int remove_disk(int mdfd, struct supertype *st,

 	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.

-- 

2.7.4