Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=5792a2856a63cdc568e08a7d6f9b2413d9217b3e
Commit: 5792a2856a63cdc568e08a7d6f9b2413d9217b3e
Parent: 456a09dce9ca9b0013cabcda918aee851a04471d
Author: NeilBrown <[EMAIL PROTECTED]>
AuthorDate: Wed Apr 4 19:08:18 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Wed Apr 4 21:12:47 2007 -0700
[PATCH] md: avoid a deadlock when removing a device from an md array via
sysfs
A device can be removed from an md array via e.g.
echo remove > /sys/block/md3/md/dev-sde/state
This will try to remove the 'dev-sde' subtree which will deadlock
since
commit e7b0d26a86943370c04d6833c6edba2a72a6e240
With this patch we run the kobject_del via schedule_work so as to
avoid the deadlock.
Cc: Alan Stern <[EMAIL PROTECTED]>
Signed-off-by: Neil Brown <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
drivers/md/md.c | 16 +++++++++++++++-
include/linux/raid/md_k.h | 1 +
2 files changed, 16 insertions(+), 1 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2a9b6a0..509171c 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1378,6 +1378,12 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t
* mddev)
return err;
}
+static void delayed_delete(struct work_struct *ws)
+{
+ mdk_rdev_t *rdev = container_of(ws, mdk_rdev_t, del_work);
+ kobject_del(&rdev->kobj);
+}
+
static void unbind_rdev_from_array(mdk_rdev_t * rdev)
{
char b[BDEVNAME_SIZE];
@@ -1390,7 +1396,12 @@ static void unbind_rdev_from_array(mdk_rdev_t * rdev)
printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
rdev->mddev = NULL;
sysfs_remove_link(&rdev->kobj, "block");
- kobject_del(&rdev->kobj);
+
+ /* We need to delay this, otherwise we can deadlock when
+ * writing to 'remove' to "dev/state"
+ */
+ INIT_WORK(&rdev->del_work, delayed_delete);
+ schedule_work(&rdev->del_work);
}
/*
@@ -3389,6 +3400,9 @@ static int do_md_stop(mddev_t * mddev, int mode)
sysfs_remove_link(&mddev->kobj, nm);
}
+ /* make sure all delayed_delete calls have finished */
+ flush_scheduled_work();
+
export_array(mddev);
mddev->array_size = 0;
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index 8245c28..de72c49 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -104,6 +104,7 @@ struct mdk_rdev_s
* for reporting to userspace and
storing
* in superblock.
*/
+ struct work_struct del_work; /* used for delayed sysfs removal */
};
struct mddev_s
-
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