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>

diff --git a/Grow.c b/Grow.c
index 218a70649c1f8cb582f7b9a32f55c5d3ce85e170..e22661ca3dff1788d6d59a423e748c99cd294556 100755 (executable)
--- 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 edf5798aa87d9b9b45dbb6caa107487be7a815aa..55218d9b0a7d52e7a114982704de8ca8422efdde 100644 (file)
--- 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 b855d242803f59e0bbf5632b3d522e4134e13828..cebc0c0a249f9c976fe5ca84a63abcf533679f0c 100644 (file)
--- 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 b7185316324863f85aae5b81eedced0901a1eb45..683c869af83788a5e308b410e9faf78241f2b330 100644 (file)
--- 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 &&