[PATCH v2] Remove: container should wait for an array to release a drive
DORMANTno replies
From: Tomasz Majchrzak <hidden>
Date: 2016-07-20 08:01:05
Subsystem:
the rest · Maintainer:
Linus Torvalds
A 'faulty' drive is being removed from a container after it has been released by an array, however there is a race there. The drive is released asynchronously by a monitor but sometimes it doesn't happen before container checks it. It results in a container refusing to remove a drive as it still seems to be a part of some array. It seems 'ping_monitor' could be a solution here to assure monitor has had a chance to process the events, however it doesn't resolve the problem - sometimes an array has to request a release of the drive few times (as the array is busy) and single 'ping_monitor' call is not sufficient. As there is no way to query monitor progress, it forces us to retry a check several times before an error is returned. Signed-off-by: Tomasz Majchrzak <redacted> --- Manage.c | 38 +++++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 13 deletions(-)
diff --git a/Manage.c b/Manage.c
index e2e88b8..7f8eb88 100644
--- a/Manage.c
+++ b/Manage.c@@ -1125,19 +1125,31 @@ int Manage_remove(struct supertype *tst, int fd, struct mddev_dev *dv, */ if (rdev == 0) ret = -1; - else - ret = sysfs_unique_holder(devnm, rdev); - if (ret == 0) { - pr_err("%s is not a member, cannot remove.\n", - dv->devname); - close(lfd); - return -1; - } - if (ret >= 2) { - pr_err("%s is still in use, cannot remove.\n", - dv->devname); - close(lfd); - return -1; + else { + /* The drive has already been set to 'faulty', however monitor might + * not have had time to process it and the drive might still have + * an entry in the 'holders' directory. Try a few times to avoid + * a false error */ + int count = 20; + do { + ret = sysfs_unique_holder(devnm, rdev); + if (ret < 2) + break; + usleep(100 * 1000); //100ms + } while (--count > 0); + + if (ret == 0) { + pr_err("%s is not a member, cannot remove.\n", + dv->devname); + close(lfd); + return -1; + } + if (ret >= 2) { + pr_err("%s is still in use, cannot remove.\n", + dv->devname); + close(lfd); + return -1; + } } } /* FIXME check that it is a current member */
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1.8.3.1