tree 580eb7ef4129964a221c3e802700cf259c0b8dce
parent 3d7e7e1d9db048bc6c1503bca9c82193450fc476
author NeilBrown <neilb@suse.com> 1480916450 +1100
committer Shaohua Li <shli@fb.com> 1480986663 -0800

md: fix refcount problem on mddev when stopping array.

md_open() gets a counted reference on an mddev using mddev_find().
If it ends up returning an error, it must drop this reference.

There are two error paths where the reference is not dropped.
One only happens if the process is signalled and an awkward time,
which is quite unlikely.
The other was introduced recently in commit af8d8e6f0.

Change the code to ensure the drop the reference when returning an error,
and make it harded to re-introduce this sort of bug in the future.

Reported-by: Marc Smith <marc.smith@mcc.edu>
Fixes: af8d8e6f0315 ("md: changes for MD_STILL_CLOSED flag")
Signed-off-by: NeilBrown <neilb@suse.com>
Acked-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>