diff options
| author | NeilBrown <neilb@suse.de> | 2007-04-04 19:08:18 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-04-04 21:12:47 -0700 |
| commit | 5792a2856a63cdc568e08a7d6f9b2413d9217b3e (patch) | |
| tree | 042a09fbfdf75dac5efa3bf61c7d6c6dd4c6ba7f | |
| parent | 456a09dce9ca9b0013cabcda918aee851a04471d (diff) | |
[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 <stern@rowland.harvard.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/md/md.c | 16 | ||||
| -rw-r--r-- | 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 2a9b6a07e3a2..509171ca7fa8 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 8245c282168b..de72c49747c8 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 |