From 1ab9ed2afb7ca50c4f922a0b85c4e6631becde02 Mon Sep 17 00:00:00 2001

From: NeilBrown <neilb@suse.com>

Date: Mon, 27 Mar 2017 14:36:56 +1100

Subject: [RHEL7.5 PATCH 023/169] Add 'force' flag to *hot_remove_disk().

In rare circumstances, the short period that *hot_remove_disk()

waits isn't long enough to IO to complete.  This particularly happens

when a device is failing and many retries are still happening.

We don't want to increase the normal wait time for "mdadm --remove"

as that might be use just to test if a device is active or not, and a

delay would be problematic.

So allow "--force" to mean that mdadm should try extra hard for a

--remove to complete, waiting up to 5 seconds.

Note that this patch fixes a comment which claim the previous

wait time was half a second, where it was really 50msec.

Signed-off-by: NeilBrown <neilb@suse.com>

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

---

 Grow.c   |  2 +-

 Manage.c | 10 +++++-----

 mdadm.h  |  4 ++--

 util.c   | 10 +++++-----

 4 files changed, 13 insertions(+), 13 deletions(-)

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

index 218a706..e22661c 100755

--- a/Grow.c

+++ b/Grow.c

@@ -2749,7 +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));

-			hot_remove_disk(fd, makedev(disk.major, disk.minor));

+			hot_remove_disk(fd, makedev(disk.major, disk.minor), 1);

 		}

 	}

 	c = map_num(pers, level);

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

index edf5798..55218d9 100644

--- a/Manage.c

+++ b/Manage.c

@@ -1110,7 +1110,7 @@ int Manage_add(int fd, int tfd, struct mddev_dev *dv,

 }

 int Manage_remove(struct supertype *tst, int fd, struct mddev_dev *dv,

-		  int sysfd, unsigned long rdev, int verbose, char *devname)

+		  int sysfd, unsigned long rdev, int force, int verbose, char *devname)

 {

 	int lfd = -1;

 	int err;

@@ -1177,9 +1177,9 @@ int Manage_remove(struct supertype *tst, int fd, struct mddev_dev *dv,

 		/* device has been removed and we don't know

 		 * the major:minor number

 		 */

-		err = sys_hot_remove_disk(sysfd);

+		err = sys_hot_remove_disk(sysfd, force);

 	} else {

-		err = hot_remove_disk(fd, rdev);

+		err = hot_remove_disk(fd, rdev, force);

 		if (err && errno == ENODEV) {

 			/* Old kernels rejected this if no personality

 			 * is registered */

@@ -1603,7 +1603,7 @@ int Manage_subdevs(char *devname, int fd,

 			if (dv->disposition == 'F')

 				/* Need to remove first */

-				hot_remove_disk(fd, rdev);

+				hot_remove_disk(fd, rdev, force);

 			/* Make sure it isn't in use (in 2.6 or later) */

 			tfd = dev_open(dv->devname, O_RDONLY|O_EXCL);

 			if (tfd >= 0) {

@@ -1645,7 +1645,7 @@ int Manage_subdevs(char *devname, int fd,

 				rv = -1;

 			} else

 				rv = Manage_remove(tst, fd, dv, sysfd,

-						   rdev, verbose,

+						   rdev, verbose, force,

 						   devname);

 			if (sysfd >= 0)

 				close(sysfd);

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

index b855d24..cebc0c0 100644

--- a/mdadm.h

+++ b/mdadm.h

@@ -1476,8 +1476,8 @@ 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 sys_hot_remove_disk(int statefd);

+extern int hot_remove_disk(int mdfd, unsigned long dev, int force);

+extern int sys_hot_remove_disk(int statefd, int force);

 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 b718531..683c869 100644

--- a/util.c

+++ b/util.c

@@ -1795,15 +1795,15 @@ int remove_disk(int mdfd, struct supertype *st,

 	return rv;

 }

-int hot_remove_disk(int mdfd, unsigned long dev)

+int hot_remove_disk(int mdfd, unsigned long dev, int force)

 {

-	int cnt = 5;

+	int cnt = force ? 500 : 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.

+	 * up to 5 seconds if 'force' is set, or 50 msec if not.

 	 */

 	while ((ret = ioctl(mdfd, HOT_REMOVE_DISK, dev)) == -1 &&

 	       errno == EBUSY &&

@@ -1813,9 +1813,9 @@ int hot_remove_disk(int mdfd, unsigned long dev)

 	return ret;

 }

-int sys_hot_remove_disk(int statefd)

+int sys_hot_remove_disk(int statefd, int force)

 {

-	int cnt = 5;

+	int cnt = force ? 500 : 5;

 	int ret;

 	while ((ret = write(statefd, "remove", 6)) == -1 &&

-- 

2.7.4